Definitions

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Abdomen

Posterior part of body, of six segments or somites, sometimes including tailfan. [Poore, 2004]
Region of the body posterior to cephalothorax, consisting of six body segments and telson (see Fig. 13). [Hobbs and Jass, 1988]
That part of the body posterior to the cephalothorax, consisting of six body segments or somites plus the telson (Fig. 1).
(syn. Tail) [Perez Farfante and Kensley, 1997]
That portion of the body posterior to the cephalothorax, consisting of the telson and six body segments ot somites; the "tail". [Hobbs, Hobbs, and Daniel 1977]
The "tail or that part of the body posterior to the cephalothorax, consisting of six body segments or somites and the telson. [Chace and Hobbs, 1969]
The part of the body posterior to cephalothorax, the 'tail." [Butler, T. H.]
The posterior region of the trunk (body). [Brusca and Brusca, 2002]
The segmented hindmost part of the body held flexed forward beneath the thorax. Composed of six segments and a telson, referred to here as seven-segment. [Ingle, 1983]
Trunk somites (tagma) between thorax and telson; somites with or without limbs.
(syn. pleon) [McLaughlin, 1980]
Trunk tagma following thorax and including telson; somites either without limbs or (in Malacostraca) bearing pleopods or uropods or both; in crabs bent sharply forward under thorax and much wider in females than in males.
(syn. pleon)
See: Metasome, Urosome [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) Trunk. [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Posterior division (tagma) of body (head, thorax, abdomen), Consists of large and variable number of segments (body rings), the anterior abdominal rings each bearing several appendages. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Trunk. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Posterior division (tagma) of body (head, thorax, abdomen). Consists of eight segments (somites) and bears terminal telson with caudal rami. lacks appendages except for anterior two somites, which are fused (genital somite) and bear reproductive structures. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Posterior division (tagma) of body (cephalon, thorax, abdomen). Consists of 11 segments (somites) and bears terminal telson (anal somite) with caudal furca, With the exception of a reduced pair of appendages ("genital appendages"), abdomen lacks limbs. Thorax and abdomen together occasionally termed trunk. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Pleon. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Pleon. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Posterior division (tagma) of body (cephalothorax, abdomen). Consists of six somites (pleomeres), each bearing pair of appendages (pleopods). Sixth pleomere (with uropods) bears posterior telson. (extended, bent upon itself, folded under cephalothorax, spirally coiled; symmetrical, asymmetrical; compressed, depressed; acutely triangular, broadly triangular, broadly oval, subcircular, T-shaped; smooth, sculptured).
(syn. pleon) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Pleon. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Pleon. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Posterior of three basic divisions (tagmata) of body (head, thorax, abdomen). Consists of six somites (pleomeres) bearing posterior telson.
(syn. pleon) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Posterior division (tagma) of body (cephalon, thorax, abdomen). Consists of six somites (pleomeres), each bearing pair of appendages (pleopods). Sixth pleomere (with uropods) bears or is fused with telson. (compressed, depressed).
(syn. pleon) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Posterior division (tagma) of body (cephalon, thorax, abdomen). Consists of seven segments (somites), the first six each bearing pair of pleopods; bears telson and caudal furca posteriorly. Anterior region of abdomen covered, along with thorax and posterior part of head (cephalon), by carapace.
(syn. pleon) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Unsegmented posterior division (tagma) of body (cephalothorax, abdomen, or cephalon, pereon, abdomen). Relatively small, dorsoventrally flattened, and drawn out posteriorly into two lobes; bears pair of caudal rami and anus in cleft (sinus) between two lobes. (acorn-shaped, broadly elliptical, cordate, obcordate, obovate, spindle-shaped; lobes: acutely pointed, bluntly pointed, rounded).
(syn. pleon) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) In ascothoracican, posteriormost division (tagma) of body (head, thorax, abdomen). Consists of four or five segments (somites), the last bearing caudal furca. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Posterior and typically narrowest of three basic divisions of body (cephalon, thorax, abdomen). Consists of five somites (pleomeres), the first often being termed genital somite, the last termed anal somite (posterior to caudal rami). Typically lacks appendages. (symmetrical, asymmetrical; segmented, unsegmented).
(syn. pleon) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) That part of the body of a copepod posterior to the somite bearing the genital opening. The abdomen includes four somites, three of which do not bear a paired appendage; the posterior somite bears the caudal rami and is the first abdominal somite to appear during development. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Mystacocarida) According to interpretation dividing body into cephalon, thorax, and abdomen, last five somites of body. Lacks appendages yet bears telson and caudal furca. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Rudimentary region of body bearing caudal rami; indistinguishably fused to thorax. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Posterior of three divisions (tagmata) of body (head, throrax, abdomen). Consists basically of six somites (pleomeres) bearing posterior telson, although in bathynellacean, last pleomere is fused with telson to form pleotelson. Bears varying number of pleopods.
(syn. pleon) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Posterior of three divisions (tagmata) of body (cephalon, thorax, abdomen). Consists basically of six somites (pleomeres) bearing posterior telson. (See also pleotelson).
(syn. pleon) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Posterior division (tagma) of body (cephalo-thorax, abdomen); consists of six somites (pleomeres), the first first five bearing pleopods, the sixth bearing uropods. Bears posterior telson. [Stachowitsch, 1992]

Abdominal aorta

(Taxon-specific: Order Mysida) Posterior aorta. [Stachowitsch, 1992]

Abdominal appendage

(Taxon-specific: Order Stomatopoda) Pleopod. [Stachowitsch, 1992]

Abdominal ganglion

(Taxon-specific: Subclass Branchiura) Ganglion adjoining last thoracic ganglion in anterior region of thorax (forming last lobe of six-lobe ganglion mass). May bear smaller pair of lobes; gives rise to two pairs of nerves extending into abdomen. [Stachowitsch, 1992]

Abdominal limb

See: Pleopod, Uropod [Martin, 2005]

Abdominal process

Finger-like projection ( one to several ) on dorsal surface of cladoceran abdomen; may help to retain eggs in brood chamber. [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) Finger-like projection(s) on dorsal surface of abdomen. [McLaughlin, 1980]
(Taxon-specific: Order Cladocera) One of typically two dorsal processes projecting from border of trunk and postabdomen. Considered to serve in closing off brood chamber posteriorly.
(syn. abdominal outgrowth) [Stachowitsch, 1992]

Abdominal segment

Entire animal, right appendages omitted, dorsal view, based on Munida. [Baba, 2005]
(Figure only.) [Baba, 2005]

Abdominal seta

(Taxon-specific: Order Cladocera) One of two elaborate setae located on small protuberance on dorsal surface of postabdomen.
(syn. setae natatoriae) [Stachowitsch, 1992]

Abdominal somite

Any single division of body behind thorax.
(syn. pleomere, pleonite) [Moore and McCormick, 1969]
Any single division of body between thorax and telson.
(syn. pleomere, pleonite) [McLaughlin, 1980]
(Taxon-specific: Class Cephalocarida) One of 11 segments of abdomen. First abdominal somite ( = 9th postcephalic segment) bears reduced pair of appendages ("genital appendages"). Last abdominal somite (19th postcephalic segment) bears telson. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Pleomere. [Stachowitsch, 1992]

Abdominal spine

(Taxon-specific: Order Anostraca) Spine-shaped projection on each side of abdominal somite. [Stachowitsch, 1992]

Abreptor

Postabdomen of cladocerans, bent forward from junction with body and terminating in 2 claws with spines and teeth on their concave sides. [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) Postabdomen, bent forward from junction with body, terminating in 2 claws. [McLaughlin, 1980]
(Taxon-specific: Order Cladocera) Postabdomen. [Stachowitsch, 1992]

Acanthopod

In Cirripedia (Thoracica), appendage where rami of cirrus have setae along lesser curvature much reduced; setae of greater curvature arranged in transverse row, as strong sharp spines at each articulation (cf., ctenopod, lasiopod). [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Appendage (cirrus) with short row of strong sharp spines distally at each articulation of greater curvature and few or no spines along lesser curvature. [McLaughlin, 1980]

Acanthosoma

(Taxon-specific: Order Decapoda) Zoea. [Stachowitsch, 1992]

Accessory Antennule

(Taxon-specific: Subclass Copepoda) The atrophied and offset terminal segment of the antennary endopod. [Boxshall and Halsey, 2004]

Accessory flagellum

(Taxon-specific: Order Amphipoda) Small inner flagellum of antennule (as opposed to larger primary flagellum). Number of articles is of taxonomic importance. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) In antenna of certain isopods, small, many-segmented flagellum projecting from fourth segment of peduncle. [Stachowitsch, 1992]

Accessory flexor muscle

A small muscle which flexes the leg at the MC joint. It is in two parts, proximal and distal, and inserts on a long thin apodeme in the merus (Fig. 19). [Warner, 1977]

Accessory gill

(Taxon-specific: Order Amphipoda) One in a series of I small respiratory structures projecting from bases of coxal gills. [Stachowitsch, 1992]

Accessory gland

(Taxon-specific: Order Stomatopoda) In male reproductive system, pair of slender glands in thorax under heart; fused anteriorly and opening at tips of penes (via ducts running parallel to sperm ducts). [Stachowitsch, 1992]

Accessory heart

(Taxon-specific: Order Decapoda) Cor frontale. [Stachowitsch, 1992]

Accessory lobe

Small lobe at base of median lobe, on anterior surface of petasma in the genus Gennadas. [Perez Farfante and Kensley, 1997]
(Taxon-specific: Order Cumacea) One posteriorly directed part of epipod of first maxilliped pair, single respiratory projection set apart from series of remaining branchial lobules. [Stachowitsch, 1992]

Accomodation groove

(Taxon-specific: Class Ostracoda) Hinge structure; longitudinal groove above median hinge element. Receives dorsal edge of opposite valve. [Stachowitsch, 1992]

Acicle

Antennal scale reduced to a spine. [Williams, 1984]
Small scaphocerite or antennal scale. [Poore, 2004]
(Taxon-specific: Order Decapoda) Spine-shaped outer branch (exopod) of antenna; represents reduced antennal scale (scaphocerite). May also refer to spine-like ophthalmic scale on eyestalk. (unarmed, spinose). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Ocular scale. [Stachowitsch, 1992]

Acron

Anteriormost part of body carrying eyes, not considered to be true cephalic somite.
(syn. ophthalmic somite, presegmental region. [Some authors recognize as protocephalon anterior part of h) [Moore and McCormick, 1969]
Anteriormost part of the body carrying the eyes; not considered true cephalic somite.
(syn. opthalmic somite, presegmental region) [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Anterior segment of body (although not considered to be a true somite); bears eyestalks (ocular peduncles). Acron and first cephalic somite occasionally interpreted as representing protocephalon.
(syn. ophthalmic somite, pre-segmental region) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Anteriormost segment of body (although not considered to be a true somite); divided into three plates-fastigial, ocular, and postocular- of which the median ocular plate bears the eyestalks (ocular peduncles). Not covered by carapace, although rostrum may partially or entirely extend across acron.
(syn. opthalmic somite) [Stachowitsch, 1992]

Acumen

Pointed apical part (tip) of rostrum, frequently delineated basally by marginal spines (see Fig. 14). [Hobbs and Jass, 1988]
The apical part of the rostrum frequently delimited basally by marginal spines. [Hobbs, Hobbs, and Daniel 1977]

Acute

Tapering to sharp point. [Butler, T. H.]

Adductor muscle (of carapace)

Muscle attached to carapace for pulling it to the body (thorax) or connecting halves of bivalve shell (e.g. Conchostraca, Ostracoda, Leptostraca) or valves of cirriped capitulum for closure of them. In Cirripedia, any transverse muscles, particularly that of maxillary segment, for closure of aperture; in Thoracica, adductor (adductor scutorum) acts upon scutal plates or valves. [Moore and McCormick, 1969]
(Taxon-specific: Order Diplostraca) Well-developed muscle attaching each side of head region to carapace. (See also ligament). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Carapace adductor muscle. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Conspicuous transverse muscle joining both scuta and serving to close aperture. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Muscle attached to carapace for pulling it to body or connecting halves of bivalve carapace. [McLaughlin, 1980]
(Taxon-specific: Class Ostracoda) Well-developed transverse muscle extending from body to inner surface of each valve. Forms characteristic muscle scars on valves and serves to close carapace. [Stachowitsch, 1992]

Adductor muscle scar pattern

(Taxon-specific: Class Ostracoda) Rather central pattern of scars (raised or depressed) indicating where central adductor muscles attach to valves; not always clearly visible. [Cohen, Peterson, and Maddocks, in press]

Adductor pit

In cirripeds, depression on interior of scutum for attachment of adductor muscle, located between adductor ridge and occludent margin. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature: on inner surface of scutum, depression marking attachment point of adductor muscle. In unstalked barnacle, located between adductor ridge and occludent margin. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Depression on inner surface of scutum between adductor ridge and occludent margin for attachment of adductor muscle (thoracic Cirripedia). [McLaughlin, 1980]

Adductor ridge

In cirripeds (Balanomorpha), linear elevation on interior of scutum between adductor pit and tergal margin. [Moore and McCormick, 1969]
Linear elevation on inner surface bounding adductor pit on tergal pit in sessile barnacles. [McLaughlin, 1980]
Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature: on inner surface of scutum in unstalked form, linear elevation between adductor muscle pit and tergal margin. [Stachowitsch, 1992]

Adhesion pads

(Taxon-specific: Subclass Copepoda) Raised areas of specialised integument, ornamented with fine ridges, found in some siphonostomatoids parasitic on fish. [Boxshall and Halsey, 2004]

Adhesive gland

(Taxon-specific: Subclass Cirripedia) Cement gland. [Stachowitsch, 1992]

Adont hinge

(Taxon-specific: Class Ostracoda) Single element hinge, bar on one valve fits into groove of other valve. [Cohen, Peterson, and Maddocks, in press]

Adrostal carina

Ridge flanking the rostrum, sometimes nearly reaching the posterior margin of the carapace (Fig. 2B). [Perez Farfante and Kensley, 1997]

Adrostral ridge

Ridge parallel to and separated by narrow groove from rostrum (Penaeoidea). [Poore, 2004]

Adrostral sulcus

Groove flanking the rostrum mesial to the adrostral carina, sometimes nearly reaching the posterior margin of the carapace (Fig. 2B). [Perez Farfante and Kensley, 1997]

Aesthetasc seta

Confined to antennule; thin-walled, smooth, non-tapering seta, rounded tip; without pore; annulus not evident. [Ingle, 1992]

Aesthetascs

See: Esthetasc [Martin, 2005]
A long, tubular, sensory seta having thin cuticle, found on the antennula or antenna. Aesthetascs may have a chemosensory function, because males generally have more of these structures than females. [Wilson, 1989]
Sensory seta covered by delicate cuticle, often projecting from antenna or antennule.
(syn. olfactory hair, esthetasc, esthete...) [McLaughlin, 1980]
Simple, tubular, thin-walled, chemosensory seta often found on the antennular flagellum. [Holdich and Jones, 1983]
Spinelike cuticular processes often occurring in clumps or rows and functioning in chemoreception, usually located on the antennules. [Brusca and Brusca, 2002]
(Taxon-specific: Order Cladocera) One in a tuft of sensory projections at tip of each antennule.
(syn. esthete, olfactory seta) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Elongate sensory projection at tip of each antennule.
(syn. esthete) [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) One in a series of sensory projections on main flagellum of antennule. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) One in a series of sensory projections on flagella of antennules. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) One in a series of small sensory projections on outer flagellum of antennule.
(syn. esthetasc, esthete, olfactory hair) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) One in a series of thin-walled sensory projections on antennule.
See: Calceolus [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) One in a series of sensory projections on antennules. (uniramous, biramous, triramous). [Stachowitsch, 1992]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Thin-walled chemosensory seta usually found on antennular flagellum. [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Thin-walled sensory seta usually on flagellum of antennule. [Kensley and Schotte, 1989]
(Taxon-specific: Order Leptostraca) One in a series of sensory projections on antennules and ocasionally also on antennae. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) A thin-walled, sensory element with putative chemoreceptive function, found on the antennules. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) A transformed seta of antenna 1 or another oral appendage of copepodids. An aesthetasc usually has a sclerotized base but otherwise is poorly sclerotized; it often is considered to have a chemosensory function. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) One in a series of small sensory projections along antennule.
(syn. esthetasc, esthete) [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Small sensory projection at tip of each antennule.
(syn. aesthete) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) One in a series of small sensory projections along antennule or antenna; considered to be modified setae. [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) One of numerous robust, long sensory projections aggregated in several dense rows at base of antennules (on pad on first article of peduncle); directed posteriorly and partially covering antennae.
(syn. esthetasc, esthete, olfactory hair) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) One of several senory projections on larger of two flagellaf antennule. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) One in a series of small sensory projections on each antennule. [Stachowitsch, 1992]

Afferent branchial channels

Pair of channels between ridges, supplying water to branchial cavity and opening in front of chelipeds or alongside epistome (some Brachyura). [Poore, 2004]

Afferent channels

Opening through which water passes to gills. [McLaughlin, 1980]
Openings through which water passes to gills, in brachyuran crabs generally located in front of bases of chelipeds. [Moore and McCormick, 1969]
Openings through which water passes to gills. In brachyuran crabs, usually opening behind pterygostomian regions and in front of chelipeds except in certain Oxystomata in which they open at anterolateral angles of palate or endostome. [Williams, 1984]

Afferent respiratory channels

Channels through which water passes to the gills, that open in front of the chelipeds and behind the pterygostomial region except in some oxystomata where they open at the sides of the endostome.
(syn. afferent branchial channels) [Ingle, 1980]
(Taxon-specific: Order Decapoda) Opening through which water enters branchial chamber under carapace. Typically applied to more restricted opening in crab-like (brachyuran) decapod; located anteroventrally on each side of body, either behind pterygostomial regions or in front of chelipeds.
(syn. afferent branchial channel)
See: Efferent respiratory channels [Stachowitsch, 1992]

Ala

One of pair of posteriorly directed cephalic-shield extensions; in cirripeds (Balanomorpha), triangular lateral part of compartment plate delimited from paries, which is overlapped by adjacent compartment plate with or without radius.
(pl. alae) [Moore and McCormick, 1969]
(Taxon-specific: Subclass Branchiura) One of two posterolateral extensions of carapace. (broad, broadly rounded, narrowly rounded, elongate and coiled behind thorax, greatly elongated; extending to second, third, or fourth thoracomere, to abdomen, beyond abdomen). [Stachowitsch, 1992]
Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature: in unstalked form, triangular lateral part of compartmental plate. Delimited from median part (paries) and overlapped by lateral part (radius) of adjoining compartmental plate. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) One of pair of posteriorly directed cephalic-shield extensions (Branchiura and some parasitic Copepoda); triangular lateral part of compartmental plate, with or without radii, overlapped by adjacent compartmental plate (balanomorph Cirripedia).
(pl. alae) [McLaughlin, 1980]
(Taxon-specific: Subclass Copepoda) In parasitic copepod, one of two posterolateral extensions of cephalic shield. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Wing-like extension of valve, typically located ventrally and directed posteriorly. (simple, carinate). [Stachowitsch, 1992]

Aliform apophyses

Incurved anterior and posterior extremities of growth lines (e.g., Conchostraca, characteristic of Ipsilonia). [Moore and McCormick, 1969]
(Taxon-specific: Order Diplostraca) Incurved anterior and posterior extremities of growth lines. [McLaughlin, 1980]

Alimentary tract

Tubular organ comprising the oesophagus, foregut, hepatopancreas, and hindgut. [Holdich and Jones, 1983]

Allometric growth

Growth of one part of the body relative to another part in which there is a change in relationships of proportions and/or shape. [Ingle, 1983]

Ambulatory leg

See: Pereiopod [Moore and McCormick, 1969]
See pereopod. [McLaughlin, 1980]
(Taxon-specific: Order Isopoda) (as applied to pereopods). Used for walking. [Kensley and Schotte, 1989]

Ambulosome

The part of the thorax of munnopsid isopods that bears the walking legs. It consists of pereonites 1-4. [Wilson, 1989]

Ambulosomite

A body segment of the ambulosome. [Wilson, 1989]

Amphidont hinge

(Taxon-specific: Class Ostracoda) A modified entomodont hinge in which the four elements are well differentiated (Families Hemicytheridae, Trachyleberididae). [Cohen, Peterson, and Maddocks, in press]

Ampulla

(Taxon-specific: Order Amphipoda) One in a series of spinose and setose ridges surrounding border between esophagus and stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) One of two spinose or setose internal ridges on each side of foregut. Serves in crushing food. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) In digestive tract, diverticulum at junction of posterior (pyloric) stomach, digestive ceca, and midgut.
(syn. pars ampullaris) [Stachowitsch, 1992]

Anal flap

(Taxon-specific: Class Remipedia) Small lobe covering anus at posterior end of anal segment. [Stachowitsch, 1992]

Anal furca

(Taxon-specific: Subclass Branchiura) Caudal ramus. [Stachowitsch, 1992]

Anal operculum

(Taxon-specific: Subclass Copepoda) A small median process on dorsal surface of the anal somite protecting the anus. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) Lid-like structure covering anus. (smooth, toothed). [Stachowitsch, 1992]

Anal papilla

(Taxon-specific: Subclass Branchiura) Caudal ramus. [Stachowitsch, 1992]

Anal segment

(Taxon-specific: Order Diplostraca) Telson.
(syn. anal somite) [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Telson.
(syn. anal somite) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Telson.
(syn. anal somite) [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Posteriormost segment of body; partially fused to reduced last trunk segment and bearing both anus and caudal rami. Occasionally also referred to as telson. (Length longer than, equal to, or shorter than width). [Stachowitsch, 1992]

Anal somite

Postsegmental plate or lobe bearing anus. [Brusca and Brusca, 2002]
(Taxon-specific: Order Leptostraca) Telson.
(syn. anal segment) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Last (fifth) segment of abdomen; bears anus dorsally and pair of caudal rami posteriorly. Occasionally termed telson. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The posterior somite and abdominal somite onto which the anus opens. The anal somite bears a paired appendage called the caudal rami. The anal somite is considered the first abdominal somite, despite its posterior position, because it is the first abdominal somite to appear during post-embryonic development. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Mystacocarida) Telson. [Stachowitsch, 1992]

Anal spines

Single row of spines on either side of cladoceran postabdomen (e.g., Sididae, Holopedidae, Daphniidae). [In addition, some cladocerans possess lateral spines (e.g., Macrothricidae, Chydoridae).]. [Moore and McCormick, 1969]
Single row of spines on either side of postabdomen (cladocera) or prominent telsonal spines (Conchostraca). [McLaughlin, 1980]
(Taxon-specific: Order Cladocera) One in a series of spines along (morphological) dorsal surface of postabdomen.
(syn. anal tooth) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) One of two blade-like, serrate spines projecting from posterodorsal end of telson. [Stachowitsch, 1992]

Anameric

The addition of only one somite to the body at each molt during development. [Ferrari and Dahms, in press]

Anamorphic development

In which a series of similar larval stages are passed through after hatching. [Ingle, 1992]
Indirect development in which the embryo hatches as a nauplius larva and the adult form is achieved via a series of gradual changes in body morphology as new segments and appendages are added. [Brusca and Brusca, 2002]

Androdioecy

Rare type of mixed mating system in which males coexist with hermaphrodytes but there are no true females. [Brusca and Brusca, 2002]

Androgenic gland

(Taxon-specific: Order Decapoda) In male, small gland associated with terminal end of each vas deferens. Secretes hormones stimulating spermatogenesis and development of secondary sex characteristics. [Stachowitsch, 1992]

Anecdysis

A prolonged period without ecdysis; occurs in crustaceans that molt seasonally. [Bliss, 1982]
An intermoult stage in which all tissue growth has been completed. [Ingle, 1983]

Angulate

(Taxon-specific: Order Isopoda) Having an angle or an angular shape. [Kensley and Schotte, 1989]

Annulate seta, with setules

These are always mechanoreceptors; they always form in invaginated pockets, may be of a variety of sizes and shapes, may have the setules distributed along the shaft in many kinds of patterns, and may have denticules distally along the shaft. [Watling, 1989]

Annulate seta, without setules

These usually are chemoreceptive, but may be mechanoreceptive in large groups; they always form in invaginated pockets and may be smooth or denticulate, elongate and stiff, or short and robust. [Watling, 1989]

Annulations

Spaced rings on a segment of appendage, not articulated, yet wth flexability. [Butler, T. H.]

Annulus

A faint ring circumscribing the shaft; may be located near the base or well along the shaft. [Watling, 1989]

Annulus ventralis

Crayfish seminal receptacle, consisting of median sclerite between fourth and fifth pereiopods; the spermatophore receptacle on sternum of female (see Fig. 23d). [Hobbs and Jass, 1988]
Seminal receptacle of cambarids, consisting of a median sclerite between the fourth and fifth pereiopods. [Hobbs, Hobbs, and Daniel 1977]
Seminal receptacle of female crayfish. [McLaughlin, 1980]

Anomura

A suborder of decapod crustaceans in which the fifth pair of pereiopods are extremely reduced and often concealed beneath the carapace; the antennae are placed to the outside of the eyestalks and the sub-hepatic regions of the carapace are not fused with the endostome. (Hermit crabs, Porcelain crabs, Lithodid crabs). [Ingle, 1980]

Anomuran crabs

Hermit crabs; coconut crab; also crab-like members of the infraorder Anomura, in which the last (fifth) pair of thoracic legs is very small and often kept hidden within the branchial chambers. [Bliss, 1982]

Anomuran seta

A small (pappose-type seta in species studied) occuring on or near the outermost part of the telson posterior margin in anomuran larvae (and also Dromia), and distinct from all other types of telson setae. [Ingle, 1992]

Antenna

Antennal peduncle consisting of 5 articles, based on Uroptychus. [Baba, 2005]
(Figure only.) [Baba, 2005]
Mobile sensory appendages arising below the eyes at the front of the head. There are two pairs of these appendages, the first and second antennae. The first antennae are uniramous and may have two or three flagellae each. The second antennae are biramous, one branch being similar in gross form to the first antenna, the other being flattened and scale-like (referred to as a scale). [Mauchline, 1984]
More lateral of the two paired, usually flagellate appendages projecting distally from the anterior end of the cephalothorax (Fig. 1).
(pl. antennae) [Perez Farfante and Kensley, 1997]
One of pair of anterior appendages of head region placed morphologically next behind antennule, uniramous in some crustaceans but biramous in all nauplii and in adults of most classes; may be extremely long and composed of multitudinous small segments or reduced to mere rudiment or lacking.
(syn. second antenna) [Moore and McCormick, 1969]
One of pair of appendages of second cephalic somite.
(syn. 2nd antenna) [McLaughlin, 1980]
Second cephalic appendage, usually with peduncle of five articles and multiarticulate flagellum (sometimes antenna 2); plural sometimes used to refer to both antennules and antennae.
(pl. antennae) [Poore, 2004]
Second pair of cephalic appendages (antenna 2). [Holdich and Jones, 1983]
The appendages of the second and third head segments are the first and second pairs of antennae respectively. The first antennae are secondarily biramous (Fig. 3) Both pairs of antennae are sensory. [Warner, 1977]
The more lateral of the the two paired flagellate appendages projecting anteriorly from anterior end of the body.
(pl. antennae) [Butler, T. H.]
The more lateral of the two paired flagellate appendages projecting anteriorly from the anterior end of the body.
(pl. antennae) [Chace and Hobbs, 1969]
The second pair of appendages situated between the antennules and the orbits, sometimes referred to as second antennae. [Ingle, 1983]
The second, paired, cephalic appendage. It consists of four short, robust, proximal segments, two long, intermediate segments, and a long series of tapering annuli, called the flagellum. The third basal segment bears a smaller, lateral appendage called the antennular scale that is homologous to the exopod in other Crustacea.
(syn. second antenna) [Wilson, 1989]
Whiplike, generally long sensory organ arising from anterior region of cephalothorax (see Figs. 13, 14). [Hobbs and Jass, 1988]
(Taxon-specific: Order Cladocera) Second and much larger pair of antennae; located laterally near posterior margin of head. Biramous, consisting of relatively large basal part (peduncle) bearing two- to four-segmented dorsal and ventral branches (rami). Serves as principle locomotory organ and moved by relatively large muscles (antennal muscles). (biramous and flattened, simple and cylindrical, branched, not branched).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Second and smaller pair of antennae; uniramous, extending from each side of labrum on underside of head. (very small, vestigial, absent).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Second and much larger pair of antennae on head; biramous, consisting of long, terminally annulate basal part (protopod, with basal lobe) and pair of segmented branches (flagella, rami).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Second and larger of two pairs of antennae; uniramous, projecting ventrally from head. In female, typically unsegmented and reduced. In male, forms clasper generally consisting of exapanded basal segment (with antennal appendage) and more slender distal segment. (fused at base, not fused at base; basal segment: with/without hand; with/without finger-like process on median surface near midlength; with prominent, dorsally directed, peg-like process on median surface just below mid-length; with row of spines along median margin; with spinous pad, median protuberance, and many small distal spines; distal segment: laminate, not laminate, with/without calcar) (See also clypeus, hand).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Second pair of antennae. Biramous, consisting of two-segmented protopod, relatively short, two-segmented endopod, and longer, multi-segmented exopod. Serves in locomotion and feeding.
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Second pair of antennae; uiramous. If fully developed, consisting of proximal five-segmented peduncle and distal flagellum.
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Second, relatively small pair of antennae.
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Second and typically larger pair of antennae. Originates from second (antennal) somite of head. Biramous, consisting of basal peduncle (typically composed of protopod, endopod, and scaphocerite) and distal flagellum. Bears pore of antennal gland. (elongate, spatulate, squamiform).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Second pair of antennae. Uniramous, consisting of proximal five-segmented peduncle and distal flagellum. May bear sensory structures (aesthetascs, calceoli). (short, long; slender, robust; naked, setose, spinose; similar, sexually dimporphic; pediform).
(syn. second antenna) [Stachowitsch, 1992]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) (pl. antennae) [Wetzer et al. 1997]
Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Paired appendage of the third cephalon segment; sometimes referred to as antenna 2. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Second, usually longer appendage of cephalon. Uniramous, consisting of basal peduncle and distal lagellum. (pediform).
See: Accessory flagellum, Antennal scale [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Second pair of antennae. Biramous, consisting of peduncle bearing scale-like outer branch (antennal scale, squama, exopod) and elongate inner branch (flagellum).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Second and smaller pair of antennae; originating from second somite of head (cephalon). Biramous, consisting of basal, two-segmented peduncle, two-segmented exopod (distal segment = antennal scale), and three-segmented endopod (with distal flagellum). (See also antennule).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Second pair of antennae. Uniramous, relatively long, and consisting of three- or four-segmented peduncle and variously shaped endopod (flagellum). (peduncle: three-/four-segmented; flagellum: long with many small joints, small with few large joints).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Second pair of appendages on underside of head. Relatively short, uniramous, and consisting of four to six segments. Armed basally with large spines/hooks, terminally with smaller spines. Serves in attachment to host.
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Biramous second pair of antennae. Present, with the exception of certain ascothoracicans, only in early larval stages (nauplius).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Second and typically shorter pair of antennae on underside of head. Highly setose and serving in suspension feeding or, in certain parasitic copepods, with terminal claw and serving in attachment to host. If uniramous, outer branch (exopod) is missing. The term second antenna is often preferentially applied. (biramous, uniramous; prehensile).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The limb of the cephalon posterior to antenna 1; on most naupliar stages, it bears a distinct protopodal masticatory arthrite which is not present on copepodid stages or on non-feeding naupliar stages, especially those of species with lecithotrophic embryos.
(syn. antenna 1) [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) The second cephalic appendage. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Mystacocarida) Second and smaller pair of antennae. Biramous, consisting of basal protopod bearing nine-segmented exopod and four-segmented endopod. Serves in locomotion and feeding.
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Second pair of antennae on head. Basically biramous, consisting of basal protopod and distal endopod and exopod (the latter often being reduced). Serves, along with antennules, as chief locomotory appendage. Carapace margin may be indented (rostral notch) for antenna. (biramous, uniramous).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Second and smaller, more paddle-shaped pair of antennae on underside of head (cephalon); biramous and consisting of protopod (with two articles) bearing scale-like exopod and three-segment endopod. Endopod articles arc around anterior aspect of exopod. Setae on antenna are plumose.
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Second pair of antennae. Consists of basal peduncle and either single flagellum (stygocaridacean), single or paired (flagellum and small exopod) branches (bathynellacean), or flagellum and scaphocerite (anaspidacean). (uniramous, biramous).
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Second, relatively small pair of antennae. Uniramous, consisting of peduncle and flagellum.
(syn. second antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Second pair of antennae. Biramous, consisting of proximal single-segmented peduncle, scale-shaped outer branch (exopod = scaphocerite), and inner branch (endopod) consisting of three larger segments and multiarticulate flagellum. Peduncle bears opening of antennal gland.
(syn. second antenna) [Stachowitsch, 1992]

Antennae

The second pair of antennae. [Brusca and Brusca, 2002]

Antennal acicle

(Taxon-specific: Order Decapoda) Acicle. [Stachowitsch, 1992]

Antennal appendage

(Taxon-specific: Order Anostraca) Variously shaped process extending from basal segment of each antenna; more common in male. (conical, lamelliform, robust, slim; extending/not extending beyond basal segment of antenna; with small teeth, with large teeth; with teeth longer on one side, with teeth not greatly different in size; with/without conical processes).
(syn. basal antennal appendage) [Stachowitsch, 1992]

Antennal artery

(Taxon-specific: Order Decapoda) Artery.
(syn. antennary artery) [Stachowitsch, 1992]

Antennal carina

See: Carapace carina a [Martin, 2005]
Ridge extending posteriorly along dorsal extremity of antennal region, often continuous with antennal spine (Fig. 2B). [Perez Farfante and Kensley, 1997]
(Taxon-specific: Order Decapoda) On each side of carapace, narrow, longitudinal ridge extending posteriorly from antennal spine.
(syn. postannular crest) [Stachowitsch, 1992]

Antennal flagellum

Multiarticulate, whiplike terminal part of the antenna (Fig. 1).
(pl. antennal flagella) [Perez Farfante and Kensley, 1997]

Antennal gland

See: Green glands [Martin, 2005]
Excretory gland situated in the basal article of the antennal peduncle. [Holdich and Jones, 1983]
Nephridial excretory organs exiting via a pore at the base of the antennae. [Brusca and Brusca, 2002]
One of pair of complex excretory glands in many malacostracans with duct opening on antenna.
(syn. green gland) [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) One of two glands located in anterior region of head and consisting basically of end sac (divided into saccule and labyrinth), bladder, and excretory duct. Opens via excretory pore on basal segment (coxa) of each antenna. Functions in excretion and controls internal fluid pressure as well as ion concentration.
(syn. green gland, excretory organ) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Pair of excretory glands in head, one opening to exterior at base (peduncle) of each antenna.
See: Gland cone [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Pair of poorly developed excretory organs in head of certain isopods, one opening at base of each antenna. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Excretory gland located in head; consists of long, coiled excretory canal and bladder. Opens to exterior on basal segment of either antenna. (See also maxillary gland). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Pair of excretory glands in head, one opening to exterior at base of each antenna. (See also maxillary gland). [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Excretory organ, one opening at each base of antenna. Characteristic for larval stages and cetain parasitic copepods. (See also maxillary gland). [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) One of two excretory glands opening at base of antennae (See also maxillar gland). [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Pair of excretory glands in head, one opening to exterior at base (peduncle) of each antenna. [Stachowitsch, 1992]

Antennal groove

See: Carapace groove a [Martin, 2005]
See: Carapace grooves a [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) On each side of carapace, longitudinal groove extending posteriorly from vicinity of antennal spine. [Stachowitsch, 1992]

Antennal muscle

(Taxon-specific: Order Cladocera) One of several well-developed muscles spanning from antenna to dorsal part of head. According to position and function one may distinguish, e.g., antennal levator muscle and antennal adductor muscle. [Stachowitsch, 1992]

Antennal notch

(Taxon-specific: Order Cumacea) On each side of carapace, notch in anterior border below pseudorostrum. Antennules and occasionally antennae project through antennal notch. Lower extension of notch termed anterolateral angle or corner. (deep, shallow).
(syn. antennal sinus) [Stachowitsch, 1992]

Antennal peduncle

Basal segments of antennule from which the flagella arise. [Butler, T. H.]
Five basal segments of the antenna, from which the antenna arises distally. [Perez Farfante and Kensley, 1997]
The basal segments of the antenna, from which the flagellum arises. [Chace and Hobbs, 1969]

Antennal region

See: Carapace region a [Martin, 2005]
See: Carapace regions a [McLaughlin, 1980]
Area on lateral surface of the carapace posterior to and encompassing antennal spine. [Butler, T. H.]
Area on the lateral face of the carapace posterior to and encompasing the antennal spine. [Perez Farfante and Kensley, 1997]
The area on the lateral surface of the carapace of shrimps posterior to and encompassing the antennal spine. [Chace and Hobbs, 1969]
(Taxon-specific: Order Decapoda) In shrimp-like (natantian) decapod, one of two relatively small regions along anterolateral margin of carapace; corresponds to position of antenna. Adjoining regions include orbital, hepatic, and pterygostomial regions. [Stachowitsch, 1992]

Antennal scale

See: Stylocerite, Scaphocerite [Martin, 2005]
Bladelike exopod of antenna situated at base of antenna (see Figs. 13, 14). [Hobbs and Jass, 1988]
See scaphocerite. [McLaughlin, 1980]
See scaphocerite.
See: Scaphocerite [Poore, 2004]
The laterally ragid lamellar exopod of the antenna. [Butler, T. H.]
The laterally rigid lamellate exopod of the antenna of shrimps and crayfishes. [Chace and Hobbs, 1969]
The plate-like exopod of the antenna. [Hobbs, Hobbs, and Daniel 1977]
(Taxon-specific: Order Tanaidacea) Scale-like structure projecting from second segment of peduncle of antenna. Considered to represent outer branch (exopod). [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Scaphocerite. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Projection extending from base (peduncle) of antenna; considered to represent reduced outer branch (exopod).
(syn. squama) [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Scale-shaped outer branch (exopod) of antenna, frequently with terminal articulation. (Scale-shaped, spine-shaped).
(syn. exopod, scaphocerite, squama) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) On each (second) antenna, large, flattened terminal segment of exopod; bears setae.
(syn. scaphocerite) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Scaphocerite. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Scaphocerite. [Stachowitsch, 1992]

Antennal setae formula

(Taxon-specific: Order Cladocera) Notation specifying number of segments and number of setae per segment in dorsal and ventral branches (rami) of antenna. Example: 0-0-1-3/1-1-3.
(syn. setation formula) [Stachowitsch, 1992]

Antennal spine

See: Carapace spine a [Martin, 2005]
See: Carapace spines a [McLaughlin, 1980]
Anterior part of carapace, including ocular peduncles, based on Munidopsis. [Baba, 2005]
(Figure only.) [Baba, 2005]
A short spine usually present on or near the anterior margin of the carapace of shrimps just ventral to the orbit. [Chace and Hobbs, 1969]
A spine on, or adjacent to, the anterior margin of the carapace, immediately ventral to the orbit. [Hobbs, Hobbs, and Daniel 1977]
Short spine usually present on or near anterior margin of carapace just ventral to orbit. [Butler, T. H.]
Spine on anterior edge of carapace immediately below orbit adjacent to base of antenna (fig. 2). [Williams, 1984]
Spine on anterior margin of carapace ventral or lateral to orbit (antennal angle if spine absent). [Poore, 2004]
Spine on, or adjacent to, anterior margin of carapace and ventral to orbit (see Fig. 13). [Hobbs and Jass, 1988]
Spine situated on the anterior margin of the carapace just ventral to the orbital margin (Fig. 2A). [Perez Farfante and Kensley, 1997]
(Taxon-specific: Order Decapoda) Anteriorly directed, spine-like projection on anterior region on each side of carapace; located below orbit, adjacent to base of antenna, and may extend beyond carapace margin. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Spine. [Stachowitsch, 1992]

Antennary nerves

Nerves extending from the tritocerebrum to the antennae. [Brusca and Brusca, 2002]

Antennula

The first paired cephalic appendage. In munnopsids, it consists of a wide, flattened basal segment, two segments of intermediate thickness, and distal annular segments of varying lengths. The most distal segments generally bear aesthetascs.
(syn. first antenna, antennule) [Wilson, 1989]

Antennular artery

(Taxon-specific: Order Decapoda) Artery. [Stachowitsch, 1992]

Antennular flagellum

Multiarticulate paired filaments (sometimes flattened and lamellate) of the antennule (Fig. 3B).
(pl. antennular flagella) [Perez Farfante and Kensley, 1997]

Antennular fossette

(Taxon-specific: Order Decapoda) On each side of carapace, anteroventral depression containing basal portion of antennule.
See: Orbito-antennulary pits [Stachowitsch, 1992]

Antennular lamella

(Taxon-specific: Order Mysida) In antennule of certain mysidaceans, term occasionally applied to scale-like process projecting from last (third) peduncular segment. [Stachowitsch, 1992]

Antennular lappet

(Taxon-specific: Order Euphausiacea) On each antennule, small lobe extending dorsally from end of first peduncular segment. (bifid, laminar, obtuse, triangular).
(syn. leaflet) [Stachowitsch, 1992]

Antennular peduncle

Proximal segments of antennule, from which flagella arise. [Hobbs and Jass, 1988]
The basal segments of the antennule, from which the flagella arise. [Chace and Hobbs, 1969]
The proximal segments of the antennule, from which the flagella arise. [Hobbs, Hobbs, and Daniel 1977]
Three basal segments of the antennule, from which the flagella arise distally (Fig. 3B). [Perez Farfante and Kensley, 1997]

Antennular process

(Taxon-specific: Order Stomatopoda) Tapering dorsolateral extension on each side of first head somite (antennular somite). [Stachowitsch, 1992]

Antennular scale

See: Stylocerite [Martin, 2005]
See stylocerite. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Stylocerite. [Stachowitsch, 1992]

Antennular somite

(Taxon-specific: Order Stomatopoda) First true somite of head (cephalon); located between acron and second (antenna-bearing) somite. Bears pair of anteriorly directed antennules as well as dorsolateral antennular processes. Not covered by carapace, although rostrum may partially or entirely extend across it.
(syn. posterior dorsal plate) [Stachowitsch, 1992]

Antennular spine

(Taxon-specific: Order Decapoda) Stylocerite. [Stachowitsch, 1992]

Antennulary nerves

Nerves that innervate the antennules and connect them to the deuterocerebrum. [Brusca and Brusca, 2002]

Antennulary part

(Taxon-specific: Subclass Mystacocarida) Region of head (cephalon) anterior to cephalic constriction. Bears antennules, four ocelli, two anteromedian lobes (rostral plate), and two anterolateral (lateral) lobes. (posterolateral corner: obtuse, right-angled). [Stachowitsch, 1992]

Antennule

First cephalic appendage, usually with peduncle of three articles and two multiarticulate flagella (sometimes antenna 1). [Poore, 2004]
First pair of cephalic appendages (antenna 1). [Holdich and Jones, 1983]
First pair of feelers, or antennae. [Bliss, 1982]
Inner of two paired flagelate appendages projecting from anterior end of body. [Butler, T. H.]
More mesial of the two paired, usually flagellate appendages projecting from the anterior end of the cephalothorax (Fig. 1, 3B). [Perez Farfante and Kensley, 1997]
One of a pair of appendages of the first cephalic somite.
(syn. 1st antenna) [McLaughlin, 1980]
One of pair of appendages of the first cephalic somite; "first antenna" (Figs. 13, 14). [Hobbs and Jass, 1988]
One pair of morphologically frontmost appendages of head region, usually filiform and multiarticulate, uniramous except in Malacostraca where it is generally biramous or even triramous; may be larger or smaller than morphologically next following appendages named antennae.
(syn. antennula, first antenna) [Moore and McCormick, 1969]
The first pair of antennae. [Brusca and Brusca, 2002]
The first pair of appendages situated medially close together under the frontal region. [Ingle, 1983]
The more mesial of the two paired flagellate appendages projecting from the anterior end of the body. [Chace and Hobbs, 1969]
(Taxon-specific: Order Cladocera) First and typically much smaller pair of antennae; located ventrally near posterior margin of head. Uniramous, unsegmented, with tuft of terminal aesthetascs. (movable, immovable = fixed; fused/ not fused with rostrum; insterted/ not inserted at anterior end of ventral edge of head).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) First and larger pair of antennae; relatively short, uniramous and slender. Extends from each side of labrum anterior to antennae. (simple, obscurely segmented).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) First and much smaller pair of antennae; uniramous, typically with series of dorsal sensory papillae. (short, long; unsegmented = unjointed, with two segments, multijointed).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) First and smaller of two pairs of antennae, projecting from anterior end of head. Uniramous, either unsegmented or only superficially segmented. (with/without tuft of terminal setae).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) First pair of antennae. Uniramous, consisting of six segments; bears terminal aesthetasc. With locmomotory and sensory functions.
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) First pair of antennae. Basically biramous, consisting of proximal three-segmented peduncle bearing larger outer (main) and smaller inner (accessory) flagellum. May bear aesthetascs. (uniramous, biramous; geniculate).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) First, relatively large pair of antennae. If fully developed, biramous, consisting of proximal four-segmented peduncle and two flagella. (uniramous, biramous).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) First and typically smaller pair of antennae. Originates from first (antennular) somite of head, each consisting of basal peduncle and one or more distal flagella. Peduncle bear statocysts and stylocerites, flagella bear aesthetascs. In crab-like (brachyuran) decapod, may be folded into orbitoantennulary pit of carapace. (biramous, triramous).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) First pair of antennae. Basically biramous, consisting of proximal three-segmented peduncle bearing large outer (primary) and smaller inner (accessory) flagella. (short, long; slender, robust; naked, setose, spinose; geniculate; with/without accessory flagellum = biramous/uniramous).
(syn. first antenna) [Stachowitsch, 1992]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Antennae 1 or first antennae; anteriormost paired appendages of head (= antennula). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) First, usually shorter appendage of cephalon; typically uniramous,
consisting of basal peduncle and distal flagellum. (uniramous, biramous).
(syn. first antenna) [Stachowitsch, 1992]
Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Paired appendage of the second cephalon segment; sometimes referred to as antenna 1. [Kensley and Schotte, 1989]
(Taxon-specific: Order Mysida) First pair of antennae. Biramous, consisting of three-segmented peduncle and pair of flagella. Antennule of male may bear processes masculinus and, rarely, an additional unsegmented accessory process.
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) First and larger pair of antennae; originating from first (antennular) somite of head. Consists of slender, three-segmented peduncle and three short flagella.
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) First pair of antennae. Relatively long, basically biramous, typically consisting of four-segmented peduncle with flagelliform inner branch (endopod) and scale-like outer branch (exopod). (biramous, uniramous; fourth segment of peduncle: with/without process, with tuft of bristles). [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) First pair of appendages on underside of head. Relatively short and basically four-segmented. Bears palp and several large spines/hooks; anterior antennular spine/hook is associated with gland or sensory organ. Serves in attachment to host.
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) First pair of antennae. Present in larval (nauplius, cyprid) stages, yet typically reduced or absent in adults. Used in attachment by barnacle larvae and associated with cement glands. Well developed in adult acrothoracican and ascothoracican. (prehensile, raptorial, subchelate, uniramous).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) First and typically larger pair of antennae on underside of head. Uniramous, consisting of up to 26 articles. In male, one or both may be equipped with hinge joint for grasping female during copulation. Bears aesthetascs. Number of articles is of systematic importance. The term first antenna is often preferentially applied. (geniculate).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The anterior limb of the cephalon; it is uniramous in copepods.
(syn. antenna 1) [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) The first cephalic appendage. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Mystacocarida) First and larger pair of antennae. Uniramous, consisting of eight setose segments and occasionally bearing terminal aesthetasc.
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) First pair of antennae on head. Uniramous, typically consisting of five to eight segments. Bears setae and claws for swimming, digging, and copulation; bears one or more aesthetascs. Carpace margin may be indented (rostral notch) for antennules.
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) First and larger pair of antennae on underside of head (cephalon); biramous and consisting of basal peduncle (with two articles and bearing aesthetasc pad) and distal (dorsal and ventral) flagella. Setae on antennae are simple.
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) First pair of antennae. Consists of basal peduncle and distal flagellum (or flagella). Biramous, with tiny lappet in bathynellacean interpreted as representing second branch. (with/without statocyst).
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) First, relatively large pair of antennae. Uniramous, consisting of peduncle and flagellum.
(syn. first antenna) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) First pair of antennae. Biramous, consisting of proximal three-segmented peduncle and two distal flagella. Antennules joined to each other by setae on first peduncular segment. (with/ without antennular lappet).
(syn. first antenna) [Stachowitsch, 1992]

Antepenultimate

Second from the last; third from the end in a series. [AHD]
Third from last, as a segment of appendage. [Butler, T. H.]

Anterioposterior axis

(Taxon-specific: Subclass Copepoda) An imaginary line through the rostral area of the head and the anal segment. [Ferrari and Dahms, in press]

Front end of organism "head end." [Hobbs and Jass, 1988]
Of, pertaining to, or toward the front. [Butler, T. H.]

Anterior aorta

(Taxon-specific: Order Cumacea) Aorta. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Aorta.
(syn. cephalic aorta) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Major unpaired blood vessel arising from anterior end of heart and extending into head. May bear accessory heart (cor frontale); gives rise to series of smaller arteries supplying brain and eyestalks.
(syn. ophthalmic artery) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Aorta. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Major unpaired blood vessel arising from anterior end of heart and extending over stomach into head. Bears accessory pumping organ (cor frontale). [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Aorta.
(syn. anterior dorsal aorta) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Major unpaired blood vessel arising from anterior end of heart and extending over stomach into head. Bears accessory pumping organ (cor frontale) and gives rise to series of smaller arteries supplying brain and eyes.
(syn. first antenna) [Stachowitsch, 1992]

Anterior chamber

Second portion (after the esophagus) of the chitin-lined foregut; has often been called the cardiac stomach. [Bliss, 1982]

Anterior element

(Taxon-specific: Class Ostracoda) Hinge. [Stachowitsch, 1992]

Anterior head lobe

(Taxon-specific: Order Amphipoda) Lateral lobe. [Stachowitsch, 1992]

Anterior lappet

(Taxon-specific: Order Mysida) Pleura. [Stachowitsch, 1992]

Anterior process

Anterior part of an elongate median protuberance lying on the penultimate (XIII) thoracic sternite (Fig. 4A). [Perez Farfante and Kensley, 1997]

Anterior tubercle

Swelling or small protuberance in anterior region of carapace of Archaeostraca; polygenetic, includes the "optic tubercle" of some authors. [Moore and McCormick, 1969]

Antero-lateral teeth

Teeth situated on the antero-lateral margin of the carapace; i.e., the margin between the outer region of the orbit and the widest part of the carapace. [Ingle, 1983]

Anterolateral

Front side of a structure. [Butler, T. H.]

Anterolateral angle

(Taxon-specific: Order Cumacea) On each anterolateral margin of carapace, lower extension of antennal notch. (acute, rounded; armed, unarmed).
(syn. anterolateral corner) [Stachowitsch, 1992]

Anterolateral carina

Longitudinal ridge extending along the anterior part of carapace, ventral to gastro-orbital carina. [Perez Farfante and Kensley, 1997]

Anterolateral margin

Margin of carapace between orbit and lateral angle or spine. [Poore, 2004]

Anterolateral region

See: Carapace region a [Martin, 2005]
See: Carapace regions b [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) In crab-like (brachyuran) decapod, relatively small region along each anterolateral margin of carapace. Adjoining regions include hepatic or subhepatic regions.
See: Posterolateral region [Stachowitsch, 1992]

Anterolateral spine

Anterior part of carapace, including ocular peduncles, based on Munidopsis. [Baba, 2005]
(Figure only.) [Baba, 2005]

Anterolateral tooth

(Taxon-specific: Order Decapoda) On carapace of crab-like (brachyuran) decapod, one (or one in a series of) projection(s) along each anterolateral margin. (acute, conical, obtuse, quadrangular, spiniform, subtriangular; ciliated, denticulate, spiny; tip: acuminate, rounded). [Stachowitsch, 1992]

Antimerodont hinge

(Taxon-specific: Class Ostracoda) A median bar or groove differentiated, usually with all elements crenulate. [Cohen, Peterson, and Maddocks, in press]

Antizoea

A modified zoeal stage exhibited by some stomatopods. [Brusca and Brusca, 2002]
(Taxon-specific: Order Stomatopoda) Early larval stage of certain stomatopods; characterized by uniramous antennules, five pairs of biramous thoracopods, and no pleopods. (See also pseudozoea). [Stachowitsch, 1992]

Antorbital spine

The spine at the postero-lateral corner of the supraorbital eave in Majidae. [Ingle, 1983]

Antrum

(Taxon-specific: Subclass Copepoda) Atrium. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) In female reproductive system, invagination of ventral surface (sternite) of first abdominal segment (genital somite). Recieves common opening of both oviducts and openings of seminal receptacles.
(syn. atrium, genital atrium) [Stachowitsch, 1992]

Anus

(Taxon-specific: Order Cladocera) Posterior opening of digestive tract at end of postabdomen. (terminal, on dorsal margin). [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Posterior opening of digestive tract at end of telson; located between caudal rami and may be covered dorsally by supra-anal plate. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Posterior opening of digestive tract at end of telson. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Posterior opening of digestive tract; located terminally on telson (between caudal rami). [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Posterior opening of digestive tract. Located at end of last (sixth) pleonite or on ventral surface of telson (in the latter case occasionally divided telson into preanal and postanal parts). Flanked by pair of anal valves. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Posterior opening of digestive tract to exterior. Located on ventral surface of telson. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Posterior opening of digestive tract; located on ventral surface of telson. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Posterior opening of digestive tract to exterior; located ventrally at base of telson. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Posterior opening of digestive tract to exterior; located ventrally at base of telson. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Posterior opening of digestive tract; located on ventral surface of telson. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Posterior opening of digestive tract; located anteroventrally on telson. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Posterior opening of digestive tract; located ventrally on telson between caudal rami. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Posterior opening of digestive tract. Located at posterior end between two lobes of abdomen; typically flanked on each side by minute caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Posterior opening of digestive tract. Located near posteriormost thoracic appendages. i.e., between sixth pair of cirri; in ascothoracican at end of abdomen. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Posterior opening of digestive tract. Located terminally, on dorsal surface of last abdominal segment (anal somite); covered by anal operculum. [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Posterior opening of digestive tract; located on ventral surface of telson (anal somite). [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Posterior opening of digestive tract at end of body (thorax/abdomen). May be located either dorsal or ventral to caudal rami. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Posterior opening of digestive tract. Located on telson. (terminal, ventral). [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Posterior opening of digestive tract to exterior; apparently terminal. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Posterior opening of digestive tract; located ventrally at posterior margin of last (sixth) abdominal somite (pleomere). [Stachowitsch, 1992]

Aorta

(Taxon-specific: Order Cladocera) Heart. [Stachowitsch, 1992]
(Taxon-specific: Order Cladocera) Unpaired blood vessel extending ventroposteriorly from heart. Separated from heart by anteroventral aortic valve and splits distally into several branches. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) In circulatory system, major blood vessel exending from end of heart. One may distinguish 1) an unpaired anterior aorta extending into head and bearing a cor frontale and 2) paired posterior aortas extending to end of abdomen. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) In circulatory system, major blood vessel extending from end of heart. One may distinguish an anterior aorta extending into head and paired posterior aortas. Anterior aorta bears cor frontale.
See: Lateral artery [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Anterior aorta, dorsal aorta. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) In circulatory system, major blood vessel extending from end of heart. One may distinguish an anterior aorta extending into head and a paired or unpaired posterior aorta extending to end of abdomen. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) In circulatory system, major unpaired blood vessel extending from anterior end of heart. Extends into head and bears small accessory heart (corfrontale). [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) In circulatory system, major blood vessel extending from heart. According to position one may distinguish an anterior aorta (bearing cor frontale), a posterior aorta, and a descending aorta. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Major blood vessel leading from heart. According to position one may distinguish an anterior aorta (giving rise to antennal, antennular, opthalmic, and other cephalic arteries) and a posterior aorta. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) In circulatory system, major unpaired blood vessel extending from end of heart. One may distinguish an anterior aorta extending into head and a posterior aorta extending into abdomen; each is branched distally. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Unpaired dorsal blood vessel extending anteriorly from heart. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Unpaired dorsal blood vessel extending anteriorly from heart.
(syn. anterior aorta) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) In circulatory system of anaspidacean, major blood vessel extending from heart. According to position one may distinguish an anterior aorta extending into head, a posterior aorta extending into abdomen, and a descending aorta at level of eighth thoracic somite. (See also artery). [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) In circulatory system, blood vessel extending from end of heart. One may distinguish short anterior and posterior aortas. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Anterior aorta, descending aorta, posterior aorta. [Stachowitsch, 1992]

Aortic valve

(Taxon-specific: Order Cladocera) Anteroventral opening in heart through which blood is pumped into aorta. (See also hepatic valve). [Stachowitsch, 1992]

Apertural hook

(Taxon-specific: Subclass Cirripedia) In acrothoracican, hook-like structure protecting aperture. (See also apertural spine). [Stachowitsch, 1992]

Apertural spine

(Taxon-specific: Subclass Cirripedia) In acrothoracican, spine-like structure protecting aperture. (See also apertural hook). [Stachowitsch, 1992]

Aperture

Posteroventral opening into cirriped mantle cavity. [Moore and McCormick, 1969]
Lepas anatifera: rostral view; and left valve and cirri removed. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) In barnacle, opening through which thoracic appendages (cirri) are protruded. In stalked barnacle, bordered on each side by scutum and tergum; bordered in unstalked barnacle by operculum (paired scuta and terga in symmetrical forms, single scutum and tergum in asymmetrical forms). (See also occludent margin).
(syn. orifice) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Posteroventral opening into mantle cavity. [McLaughlin, 1980]

Apex

Upper angle of scutum or tergum of cirripeds. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature; uppermost point (angle) of plate. Typically refers to scutum, tergum, or carina. (beaked). [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Upper angle of scutum or tergum (thoracic Cirripedia). [McLaughlin, 1980]

Apical

Apex; tip. [Hobbs and Jass, 1988]
At the distal end. [Butler, T. H.]
(Taxon-specific: Order Isopoda) Relating to the apex or tip. [Kensley and Schotte, 1989]

Apicobasal ridge

In cirripeds longitudinal feature which divides tergal slip (tergum) from rest of valve.
(syn. apicobasal furrow) [Moore and McCormick, 1969]

Apicoumbonal ridge

(Taxon-specific: Subclass Cirripedia) Barnacle plate feature; in scutum of stalked form, ridge extending from upper point (apex) to umbo. [Stachowitsch, 1992]

Apodemal pit

Any of several often unpigmented depressions on the carapace of many crabs indicating the origin of an invaginated element that forms part of the internal thoracic skeleton. [Chace and Hobbs, 1969]

Apodeme

A cuticular, usually calcified invagination upon which muscles insert and which, itself, inserts by means of tough flexible cuticle onto that part of the skeleton which is moved by its muscles (Figs. 12, 13). [Warner, 1977]
Any cuticular ingrowth of body wall. [Williams, 1984]
Infold of exoskeleton for attachment of muscles. [McLaughlin, 1980]
Infold of exoskeleton serving for attachment of muscles. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) Any one of numerous infolds of exoskeleton serving for attachment of muscles (e.g., head apodeme). May be highly developed as endopleurites and endosternites to form endoskeleton. [Stachowitsch, 1992]

Apophysis

(Taxon-specific: Subclass Copepoda) A spinous process on a swimming leg segment, typically sexually dimorphic (present in male only); ma y originate as produced segmental margin, or may be derived by modification of setal element present in female. [Boxshall and Halsey, 2004]
(Taxon-specific: Class Ostracoda) Type of valve sculpture: extension of wall (murus) in reticulate pattern. May lead to pore. [Stachowitsch, 1992]

Appendage

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
(Taxon-specific: Order Isopoda) An articulated structure used for feeding, locomotion, sensory reception, e.g., mouthparts, antennae, pereopods, pleopods, uropods. [Kensley and Schotte, 1989]
(Taxon-specific: Subclass Copepoda) Paired extensions of a somite along a proximodistal axis and usually composed of serially repeated elements. Appendages of copepods include the limb of the five cephalic somites, the limb of the seven thoracic somites plus the caudal ramus of the anal segment (see also limb and swimming leg). [Ferrari and Dahms, in press]

Appendix interna

A slender rodlike lappet on the mesial ,argin of the endopod of the second through fifth pleopods of shrimps; it is provided with terminal hooked setae by which the two pleopods of a pair must be joined mesially.
(pl. appendices internae) [Chace and Hobbs, 1969]
A slender rodlike structure on the mesial border of the endopod of the second through fifth pleopods of shrimps; terminal and/or subterminal hooked setae allow the mesial joining of two pleopods of a pair. [Hobbs, Hobbs, and Daniel 1977]
Medial projection stemming from pleopodal endopods, serving to unite members of each pair of pleopods.
(syn. stylamblys) [Moore and McCormick, 1969]
Median process of pleopodal endopod uniting members of each pair.
(syn. stylamblys) [McLaughlin, 1980]
Slender lappet, sometimes rodlike, at the mesial base of the endopod of the second pleopod (dorsal to the appendix masculina) of many males.
(pl. appendices internae) [Perez Farfante and Kensley, 1997]
Slender rodlike flap on inner margin of endopod of the second to fifth pleopods of shrimp.
(pl. appendices internae) [Butler, T. H.]
Slender, rodlike structure on mesial border of endopod of second through fifth pleopods of shrimp. [Hobbs and Jass, 1988]
Small branch on inner margin of pleopod 2, triangular or rod-like, usually with clusters of hooks to attach to its pair.
(pl. appendices internae) [Poore, 2004]
Small separate branch on mesial side of pleopodal endopodite, usually tipped with hooks which interlock with opposite member in swimming. [Williams, 1984]
(Taxon-specific: Order Decapoda) Projection of inner branch (endopod) of each pleopod; serves to hook pleopod to its opposite member (for swimming).
(syn. stylamblys) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Projection of inner branch (endopod) of each pleopod. Bears hooks (retinacula) and, in first pleopod pair of male, hook-shaped and tubular processes (petasma).
(syn. stylamblys) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) In each of the four well-developed anterior pairs of pleopods, medially (inwardly) directed process at base of endopod. Serves to link pleopods together for swimming. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Medially (inwardly) directed process of each pleopod. Serves to link pleopods of each somite together for swimming. [Stachowitsch, 1992]

Appendix masculina

A lappet inserted between the appendix interna and the mesial margin of the second pleopod of most male shrimps. The presence or absence of an appendix masculina is the easiest way to distinguish males and females in most caridean shrimps, and in some families, such as the Atyidae, it is greatly enlarged, dwarfing the superimposed appendix interna, and it offers important taxonomic characters.
(pl. appendices masculinae) [Chace and Hobbs, 1969]
A setiferous lobe or rodlike structure situated between the appendix interna and the mesial margin of the mesial ramus (endopod) of the second pleopod of male shrimps. Often an important taxonomic character, the presence or absence of an appendix masculina is the easiest means of distinguishing males and females of most freshwater shrimps. [Hobbs, Hobbs, and Daniel 1977]
Accessory male organ located mesially on second pair of pleopods between endopodite and appendix interna. [Williams, 1984]
An alternative name for a stylet-like copulatory structure on the male pleopod II. This structure is not homologous to similarly named structures found in non-isopod Eumalacostraca. [Wilson, 1989]
Complex median process of 2nd ploepodal endopod of male Caridea and some other Eucarida used in copulation or spermatophore transfer. [McLaughlin, 1980]
Complex median process of endopod of second pleopods of male Caridea and some isopods; serves in copulation. [Moore and McCormick, 1969]
Flap inserted between appendix interna and inner margin of endopod of the second pleopod in most male shrimps.
(syn. appendices musculinae) [Butler, T. H.]
Lappet, sometimes scalelike, at the mesial base of the endopod of the second pleopod (ventral to the appendix interna if latter present) in some males.
(pl. appendices masculinae) [Perez Farfante and Kensley, 1997]
Lobe or rodlike structure, bearing setae, situated between appendix interna and mesial margin of endoopod of second pleopod of male shrimps. The presence or absence of this structure provides easiest means of distinguishing males from females; an important taxonomic character for palaemonids (see Fig. 73j,k). [Hobbs and Jass, 1988]
Small branch on inner margin of pleopod 2 of males, usually rod-like, proximal to appendix interna.
(pl. appendices masculinae) [Poore, 2004]
(Taxon-specific: Order Decapoda) Median process of inner branch (endopod) of second pleopod in male; serves in copulation or spermatophore transfer. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Copulatory stylet arising from medial margin of male pleopod 2 endopod, used for transfer of spermatophores in at least some species.
(pl. appendices masculinae) [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Rod-shaped median process on endopod of second pleo-pod in male; serves in sperm transfer.
(syn. male stylet) [Stachowitsch, 1992]

Aquaculture

Large-scale cultivation of aquatic organisms under controlled conditions, for use of food or for other economic purposes. [Bliss, 1982]

Area

(Taxon-specific: Order Cladocera) One in a number of somewhat arbitrarily delimited regions on lateral surface of valve. According to position one may distinguish anterior, anterodorsal, anteromedian, anteroventral, dorsal, dorsomedian, median, midanterior, middorsal, midposterior, posterior, posterodorsal, posteromedian, posteroventral, ventral, and ventromedian areas. [Stachowitsch, 1992]

Areola

Area between branchiocardiac grooves and posterior to cervical groove on dorsal surface of carapace (Astacidea and Austroastacidea). [McLaughlin, 1980]
Dorsomedial area (usually hourglass-shaped) of thoracic region of carapace of crayfishes, bounded laterally by paired arched (branchiocardiac) grooves delineating dorsomedial limits of gill chamber (see Fig. 14). [Hobbs and Jass, 1988]
See "Cardiac region". [Chace and Hobbs, 1969]
The dorsomedian area of the thoracic part of the carapace of crayfishes, bound laterally by paired arched (branchiocardiac) grooves. [Hobbs, Hobbs, and Daniel 1977]
(Taxon-specific: Order Decapoda) On dorsal surface of carapace, area between two longitudinal branchiocardiac grooves and posterior to transverse cervical groove. [Stachowitsch, 1992]

Areolation

Demarcated and usually elevated regions of the brachyuran carapace. [Martin, 2005]

Armature

(Taxon-specific: Subclass Copepoda) The setae and spines carried on the paired limbs and caudal rami. [Boxshall and Halsey, 2004]

Artery

(Taxon-specific: Order Decapoda) One of numerous blood vessels originating from aorta or directly from heart. According to position or body region/appendages supplied, one may distinguish, among others, antennal, antennular, hepatic, lateral cephalic, ophthalmic, optic, pleopodal, rostral, segmental, sternal, and subneural arteries. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) One of numerous blood vessels originating from heart or aortas. According to position one may distinguish anterior lateral or facial artery as well as three pairs of lateral arteries. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) One of numerous blood vessels originating from heart or aorta. According to position one may distinguish anterior and posterior arteries as well as a subneural artery. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) One of numerous blood vessels originating from aorta or directly from heart. According to position and mysidacean group, one may distinguish hepatic, (anterior and posterior) lateral, sternal, subneural, and ventral arteries. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) One of numerous blood vessels originating from heart or aorta. According to position or appendages supplied, one may distinguish antennal, antennular, opthalmic, lateral, and subneural arteries. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) One of numerous blood vessels originating from heart or aortas. According to position or organ supplied, one may distinguish dorsal, labral, median, and segmental arteries, the latter with podial and visceral branches. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) In anaspidacean, one of numerous blood vessels originating from heart or aorta. According to position one may distinguish seven pairs of lateral arteries and a subneural artery (arising from descending aorta). [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) One of numerous blood vessels originating from aorta or directly from heart. According to position or body region/appendages supplied, one may distinguish, among others, abdominal, antennal, antennular, anterior lateral, mandibular-maxillary, ophthalmic, posterior lateral, and sternal arteries. [Stachowitsch, 1992]

Arthrite

(Taxon-specific: Subclass Copepoda) A movable endite, used for the praecoxal endite of maxillule. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) A ventrally articulating, sclerotized extension of a protopodal segment that is moved by muscles. [Ferrari and Dahms, in press]

Arthrobranch

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
A decapod gill associated with the articular membrane between the coxa and the body wall; "joint gills." [Brusca and Brusca, 2002]
A gill arising from the articular membrane at the proximal base of the coxa of an appendage. [Hobbs, Hobbs, and Daniel 1977]
A gill arising from the junction of the limb with the body. [Ingle, 1983]
Gill attached to the articular membrane between body wall and coxa of an appendage. [Butler, T. H.]
Gill attaching to membrane between coxa and side of body, 1 or 2 pairs per somite and usually pointing upwards. [Poore, 2004]
Gill of decapods attached to articular membrane between limb and body.
(syn. arthrobranchia) [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) Gill attached to articular membrane between appendage and body.
(syn. arthrobranchiata) [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Type of gill attached to point of articulation (articular membrane) between thoracopod and body wall. If full complement is developed, may be found associated with first through seventh thoracopods (i.e., all except last pereopods).
(syn. arthrobranchia)
See: Pleurobranch, Podobranch [Stachowitsch, 1992]

Arthrobranchia

Branchia (gill) attached to the joint area between the body and the first podomere of the leg (Fig. 3C).
(pl. arthrobranchiae) [Perez Farfante and Kensley, 1997]

Arthrobranchiae

Gills attached to articular membrane between coxa of appendage and body wall. [Williams, 1984]

Arthrodial membrane

Tough flexible cuticle occurring between skeletal elements and allowing relative movement. [Warner, 1977]
(Taxon-specific: Subclass Copepoda) An unsclerotized, flexible section of the exoskeleton between the sclerotized parts of two somites or two segments. [Ferrari and Dahms, in press]

Arthrophragm

See: Endophragm [Martin, 2005]
A cuticular calcified invagination, usually in the form of a plate, which provides a rigid orgin for muscles. [Warner, 1977]
See endophragm. [McLaughlin, 1980]

Article

A segment of any limb, but usually applied to the antennula or antenna. [Wilson, 1989]
Any of the segments of a limb or appendage.
See: Coxa, Basis, Ischium, Merus, Carpus, Propodus, Dactylus [Poore, 2004]
Any one of the subdivisions of an appendage segment. [Perez Farfante and Kensley, 1997]
Individual element of crustacean appendage.
(syn. joint, segment) [Moore and McCormick, 1969]
Subdivision of antennal or antennular flagella or appendage.
See: Segment [McLaughlin, 1980]
(Taxon-specific: Order Diplostraca) One of up to 25 segments of antennal branches (rami, flagella). May also refer to segment of other appendages. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Segment of appendage. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Any segment of appendage, although often applied to segment of flagellum of antennule or antenna.
(syn. joint, segment) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) One in a series of numerous segments of flagellum at end of antenna or antennule. May also refer to segment of pereopod.
(syn. joint, segment) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Any segment of an appendage, although often applied to segments of flagella of antennules or antennae.
(syn. joint, segment) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) A single section of an appendage, with an articulation at one or both ends. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Any segment of an appendage, although often applied to segments of flagellum of antennae or antennules.
(syn. joint, segment) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) One in a series of numerous segments of flagellum at end of antennule or antenna. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) One in a series of segments of flagellum of antennule or antenna. May also refer to segment of other appendages.
(syn. joint, segment) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) One in a series of segments of thoracic appendage (cirrus) or other appendage.
(syn. joint segment) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) One in a series of up to 26 segments of flagellum of antennule (few in antenna). Number of articles is of systematic importance. May also be used to refer to segments of other appendages.
(syn. segment, joint) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) See podomere.
See: Podomere [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Class Remipedia) In antennule, one of 11 or 12 segments of larger dorsal flagellum or 3 or 8 segments of smaller ventral flagellum. Each article bears tuft of several setae at distoventral end as well as scattered setae along shaft. Last article bears terminal tuft of setae . Also synonymous with any appendage segment.
(syn. joint, segment) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Any segment of appendage, although often applied to segment of flagella of antennules and antennae.
(syn. joint, segment) [Stachowitsch, 1992]

Articular furrow

In cirripeds, groove on tergal margin of scutum or scutal margin of tergum forming part of articulation between the plates. [Moore and McCormick, 1969]
Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature: in unstalked form, linear elevation on tergal margin of scutum or scutal margin of tergum. Ridge and furrow of scutum (or tergum) articulate with corresponding structures in tergum (or scutum). [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Groove near tergal margin of scutum or scutal margin of tergum forming part of articulation between the two valves (balanomorph Cirripedia). [McLaughlin, 1980]

Articular knob

A swelling or irregularity in the integument at a joint, as on either side of a chela at the base of the movable finger or between the abdominal somites at the juncture of the terga and the pleura. [Chace and Hobbs, 1969]
Swelling or irregularity in the shell at a joint of an appendage, or between abdominal somites at the juncture of pleuron and tergum. [Butler, T. H.]

Articular membrane

The uncalcified integument at a joint, permitting movement of the exoskeleton, as between the podomeres of a pereiopod. [Chace and Hobbs, 1969]
The uncalcified integument, permitting movement of the shell, as between segments of a periopod, or between abdominal somites. [Butler, T. H.]
Uncalcified integument of a joint, permitting movement of the exoskeleton, as between the segments of a pereopod. [Perez Farfante and Kensley, 1997]

Articular ridge

In cirripeds (Balanomorpha), linear elevation on tergal margin of scutum or scutal margin of tergum close to articular furrow and with it forming articulation between these plates. [Moore and McCormick, 1969]
Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) Linear elevation on scutum or tergum bordering articular furrow and with it forming articulation between with two valves (balanomorph Cirripedia). [McLaughlin, 1980]

Ascending

Growing or directed upward. [Butler, T. H.]

Atrium oris

Preoral cavity, bounded ventrally by posteriorly directed labrum, dorsally by ventral surface of cephalon just behind mouth, and laterally by paragnaths and mandibles. [Moore and McCormick, 1969]
Preoral cavity, bounded ventrally by posteriorly directed labrum, dorsally by ventral surface of cephalon just behind mouth, and laterally by paragnaths and mandibles. [McLaughlin, 1980]
(Taxon-specific: Order Diplostraca) Large preoral cavity formed by upper lip (labrum) extending over mouth. Tips (molar processes) of mandibles extend into atrium oris. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Large preoral cavity formed by labrum extending over mouth. Mandibles (and to a lesser extent the endites or gnathobases of maxillules) extend into atrium oris. [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Cavity around mouth formed by projecting posterior margin of labrum and paragnaths; masticatory ends (incisor process, lacinia mobilis, molar process) of mandible project into atrium oris. [Stachowitsch, 1992]

Attachment disc

(Taxon-specific: Subclass Cirripedia) In female acrothoracican, anteroventral horny structure used in attachment to burrow. If somewhat elevated, referred to as attachment knob. [Stachowitsch, 1992]

Attractor epimeralis muscle

Important muscle in many decapods, inserted along line of branchiocardiac groove in carapace. [Moore and McCormick, 1969]
Prominent muscle in many decapods, inserting along line of branchiocardiac groove. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) In each side of cephalothorax, prominent muscle extending from epimeral fold to carapace, where it inserts along branchiocardiac groove (or lateral gastrocardiac marking).
(syn. tergoepimeral muscle) [Stachowitsch, 1992]

Autotomy

The voluntary shedding of a limb by snapping it off the base. [Ingle, 1983]

Bar

(Taxon-specific: Order Cladocera) Hing structure: Ridge-like projection extending along and set off from dorsal margin of one valve. Fits into accommodation groove of opposite valve. (smooth, crenulate).
(syn. hinge bar) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) One in a series of chitinous skeletal elements supporting distal end of proboscis. According to position on may distinguish groove, lateral, lateral marginal, anterior and posterior lateral oblique, and inner and outer mandibular bars. [Stachowitsch, 1992]

Basal margin

In cirripeds, lower edge of scutum or tergum or other plate. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature: lower edge of plate. Typically refers to lower edge of scutum or tergum. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Lower edge of scutum or tergum or other plate (thoracic Cirripedia). [McLaughlin, 1980]

Basal plate

(Taxon-specific: Subclass Branchiura) Spine-studded, plate-like structure on basal segment of each maxilla. (spines: alike, unlike; close together, well-separated; blunt, curved, scale-like, sharp).
(syn. maxillary plate) [Stachowitsch, 1992]

Baseoendopod

(Taxon-specific: Subclass Copepoda) The fused basis and endopod, particularly of the fifth leg in harpacticoids. [Boxshall and Halsey, 2004]

Basi-ischium

The second podomere from the base of a limb, formed from the fusion of the basis and the ischium of the primitive appendage (Figs. 1, 2). [Warner, 1977]
(Taxon-specific: Order Decapoda) Ischiobasis. [Stachowitsch, 1992]

Basial spine

Spine projecting from basis of a thoracic appendage. [Perez Farfante and Kensley, 1997]

Basicarinal angle

Intersection of basal and carinal margins of cirriped tergum. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature: corner of tergum formed by junction of basal and carinal margins. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Intersection of basal and carinal margins of tergum (thoracic Cirripedia). [McLaughlin, 1980]

Basicerite

Second or distal segment of the protopodite of antenna, to which are attached the scale and peduncle. [Butler, T. H.]
Second segment of antennal peduncle (in Caridea bearing scaphocerite). [Moore and McCormick, 1969]
Second segment of antennal peduncle, bearing scaphocerite (Caridea). [McLaughlin, 1980]
Spine on dorsal side of basis of antenna; sometimes more lateral than dorsal. [Martin, 2005]
(Taxon-specific: Order Decapoda) In antenna, term applied to second of two segments (coxicerite, basicerite) of peduncle; may bear antennal scale (scaphocerite).
See: Carpocerite, Ischiocerite, Merocerite [Stachowitsch, 1992]

Basidorsal point

(Taxon-specific: Subclass Cirripedia) In certain unstalked barnacles, cone-shaped projection at base of penis. [Stachowitsch, 1992]

Basilateral angle

In cirripeds, intersection of lateral and tergal margins of scutum.
(syn. basitergal angle) [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Basitergal angle. [Stachowitsch, 1992]

Basioccludent angle

Intersection of basal and occludent margins of cirriped scutum. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature: corner of scutum formed by junction of basal and occludent margins. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Intersection of basal and occludent margins of scutum (thoracic Cirripedia). [McLaughlin, 1980]

Basiophthalmite

Proximal segment of eyestalk, articulating with distal segment (podophthalmite) which bears corneal surface of eye. [Moore and McCormick, 1969]
Proximal segment of eyestalk, articulating with distal segment (podopthalmite) bearing corneal surface of eye. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Proximal of typically two segments (basiophthalmite, podophthalmite) of eyestalk. [Stachowitsch, 1992]

Basipod

See: Basis [Martin, 2005]
See basis. [McLaughlin, 1980]

Basis

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
Article 2 of thoracic and abdominal appendages. [Holdich and Jones, 1983]
Limb segments adjoining coxa on its distal side and commonly bearing endopod and exopod; in nonpedunculate cirripeds comprises basal calcareous or membranous plate which furnishes anchorage to foreign body or substrate.
(syn. basipod(ite)) [Moore and McCormick, 1969]
Second article (from body) of leg or maxilliped. Sixth segment from distal end of limb.
(syn. basipodite) [Williams, 1984]
Second article of limb.
(pl. bases) [Poore, 2004]
Second podomere or segment, from the proximal end of a typically 7-segmented appendage (Fig. 3C).
(pl. bases) [Perez Farfante and Kensley, 1997]
Second segment (from proximal end) of segmented appendage. [Hobbs and Jass, 1988]
Second segment from the proximal end of a typically 7-segmented appendage.
(pl. bases) [Butler, T. H.]
Second segment of a pereiopod or maxilliped counted from the proximal end, immovably united with the ischium. [Ingle, 1983]
Segment of protopod adjoining coxa and carrying exopod and endopod distally; also basal calcareous or membranous plate furnishing anchorage to substrate in sessile cirripeds.
(pl. bases) [McLaughlin, 1980]
The second segment from the proximal end of a segmented appendage. [Hobbs, Hobbs, and Daniel 1977]
The second segment from the proximal end of a typically 7-segmented appendage.
(pl. bases) [Chace and Hobbs, 1969]
The second segment of a thoracic limb.
See: Pereopod [Wilson, 1989]
(Taxon-specific: Order Cladocera) Second segment of appendage; from distal segment of protopod (coax, basis). Often fused and indistinguishable.
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Protopod. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Elongate second segment of thoracopod (maxillipeds and pereopods) or pleopods. May bear five-segmented endopod and smaller exopod. (See also epipod). [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Second of seven segments (coxa, basis, ischium, merus, carpus, propodus, dactylus) of thoracopod. Bears endite in maxillae and maxillipeds.
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Second segment of appendage (thoracopod); forms distal segment of protopod (coxa, basis) and bears variously developed branches (endopod, exopod). May be fused to following segment (ischium) to form ischiobasis.
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Second of seven segments of thoracopod (coxa, basis, ischium, merus, carpus, propodus, dactylus); represents first movable (free) segment.
(syn. basipodite) [Stachowitsch, 1992]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) (Figure only.) [Wetzer et al. 1997]
Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Article of appendage adjoining coxa proximally, and carrying endopod distally, i.e., article 2 of pereopod. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Second segment of pereopod; located between coxa and ischium.
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Second of two segments (coxa, basis) of proximal part (protopod) of appendage.
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Third segment of thoracic appendage (thoracopod); located between coxa and merus. Also interpreted as being second segment (between coxa and ischium).
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) In thoracopod, third of three segments (precoxa, coax, basis) of protopod; may also be applied to segment of antennule.
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Basal element by which unstalked barnacle is attached to substratum. (calcareous = solid, membranous). [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Second segment of appendage; forms distal segment of protopod (coxa, basis).
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The distal segment of the protopod of postantennulary appendages, bearing the rami. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) The distal segment of the protopod; it bears no more than two ventral, setose endites. The rami, exopod and endopod of a limb, originate on the basis (see coxa and praecoxa). [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Mystacocarida) Protopod. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Distal part of divided protopod (separated from coxa by suture). [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Superorder Syncarida) Second of two segments (coxa, basis) of proximal part (protopod) of appendage.
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Second of two segments (coxa, basis) of proximal part (protopod) of appendage. Frequently interpreted as being fused with following segment (ischium) in maxilliped endopod.
(syn. basipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Second segment of appendage; forms distal segment of protopod (coxa, basis) and bears variously developed branches (endopod, exopod). Typically specified only when referring to thoracopods.
(syn. basipodite) [Stachowitsch, 1992]

Basiscutal angle

Intersection of basal and scutal margins of cirriped tergum. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature; corner of tergum formed by junction of basal and scutal margins. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Intersection of basal and scutal margins of tergum (thoracic Cirripedia). [McLaughlin, 1980]

Basitergal angle

Intersection of basal and tergal margins of cirriped scutum. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature; corner of scutum formed by junction of basal and tergal margins.
(syn. basilateral angle) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Intersection of basal and tergal margins of scutum (thoracic Cirripedia). [McLaughlin, 1980]

Bathypelagic

Zone in the ocean deeper than 1000 m below the surface, or pertaining to its inhabitants. [Butler, T. H.]

Beak

(Taxon-specific: Class Ostracoda) Downwardly directed (anteroventral) projection of carapace margin. Not equivalent to rostrum and not associated with rostral notch. [Stachowitsch, 1992]

Beaked apex

In cirripeds (Balanomorpha), upper angle of tergum produced into long narrow point. [Moore and McCormick, 1969]

Bellonci organ

(Taxon-specific: Class Ostracoda) Organ projecting from forehead or naupliar (medial) eye of most Myodocopa. [Cohen, Peterson, and Maddocks, in press]

Bender muscle

The muscle which bends the leg forward at the CP joint.
See: Abdominal spine, Cephalothorax [Warner, 1977]

Biarticulate

Consisting of two articles or segments. [Wilson, 1989]
(Taxon-specific: Order Isopoda) Composed of two articles. [Kensley and Schotte, 1989]

Bidentate

(Taxon-specific: Order Isopoda) Having two teeth. [Kensley and Schotte, 1989]

Bifid

A structure with two distal tips, as in unequally bifid seta. [Wilson, 1989]
Split in two, as in spines. [Butler, T. H.]
(Taxon-specific: Order Isopoda) Divided into two lobes or parts by a cleft. [Kensley and Schotte, 1989]

Biformes

Carapaces reflecting sexual dimorphism (e.g., Conchostraca), marked by differing valve proportions for each sex of same species (DADAY); a given species may have carapaces that are "biformes.". [Moore and McCormick, 1969]
Carapaces reflecting sexual dimorphism (e.g., Conchostraca), marked by differing valve proportions for each sex of the same species. [McLaughlin, 1980]

Bifurcate

Forked, divided into two branches. [Butler, T. H.]

Bilobed

(Taxon-specific: Order Isopoda) Composed of two lobes. [Kensley and Schotte, 1989]

Bioluminescene

Production of light by living organisms; occurs in several genera of shrimps. [Butler, T. H.]

Biramous

Having two branches or rami (exopodite and endopodite). [Holdich and Jones, 1983]
Having two branches, a typical condition for most primitive crustacean appendages. [Wilson, 1989]
Having two branches, as a pleopod. [Butler, T. H.]
Having two branches, as in the basic appendage (Fig. 2). [Warner, 1977]
Having two branches. Crustacean appendage with two rami; also antennule or antenna with two flagellar elements. [McLaughlin, 1980]
Two-branched; crustacean limb in which basis bears both exopod and endopod. [Moore and McCormick, 1969]
(Taxon-specific: Order Isopoda) Composed of two rami or branches. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Composed of two rami or branches. [Wetzer et al. 1997]
(Taxon-specific: Subclass Copepoda) Two-branched, used of limbs possessing both endopod and exopod. [Boxshall and Halsey, 2004]

Biserial branch

Primary branch of dendrobranchiate gill subdivided into two rows or series. [McLaughlin, 1980]

Biunguiculate

(Taxon-specific: Order Isopoda) Having two claws, as in a bifid dactylus. [Kensley and Schotte, 1989]

Bladder

(Taxon-specific: Order Decapoda) Expanded section of antennal gland between end sac and excretory pore. Consists of simple vesicle or is subdivided into a number of lobes or elongate diverticula extending into different regions of body. [Stachowitsch, 1992]

Blind capsule

(Taxon-specific: Subclass Branchiura) In male reproductive system, pair of glands in anterior region of thorax. Duct from each blind capsule connects to vas deferens and leads to common ejaculatory duct and gonopore.
(syn. blind gland) [Stachowitsch, 1992]

Blood pump

(Taxon-specific: Subclass Cirripedia) Rostral sinus. [Stachowitsch, 1992]

Blood rooms

Network of anastomosing cavities in body of conchostracans which provide for circulation of blood (SARS). [Moore and McCormick, 1969]

Body articulation

(Taxon-specific: Subclass Copepoda) Point at which body is capable of bending to greatest extent. Region of body anterior to flexure point is termed prosome, that posterior to it, urosome. According to group, it is located either between third/fourth, fourth/fifth, fifth/sixth thoracic somites or between sixth thoracomere and genital somite.
(syn. body flexure, flexure point) [Stachowitsch, 1992]

Body chamber

In cirripeds, interior of shell contaning soft parts of animal. [Moore and McCormick, 1969]

Body of mandible

See: Mandible body [Martin, 2005]

Body ring

Combined tergite and sternite of single somite, bearing legs or legless (as used by some specialists on Notostraca, not equivalent to somite). [Moore and McCormick, 1969]
(Taxon-specific: Order Notostraca) One in a series of divisions of thorax and abdomen. Posterior body rings may bear more than one pair of appendages each and are therefore considered to consist of several fused segments. May be modified to form half rings or spiral rings. (with leg, apodous).
(syn. ring) [Stachowitsch, 1992]

Body somite

Generally refers to unit division of thorax + abdomen in contrast to cephalic somite. [Moore and McCormick, 1969]

Boletate

A tubercle with a thick stem that is expanded distally into a convex or flat-topped surface with a circumference broader than the stem and that is usually punctate or marginally striate. [Ingle, 1980]

Bopyridum

Postlarva of epicaridean isopod that is attached to permanent host. [McLaughlin, 1980]

Boss

A globular, often polished, protrusion from the carapace surface. [Ingle, 1983]
An expanded portion (rounded protuberance) on mesial surface of coxa of fourth pereiopod of male crayfish (see Fig. 14). [Hobbs and Jass, 1988]

Brachium

(Taxon-specific: Subclass Copepoda) The digital segment of the maxilla of some siphonostomatoid copepods, corresponding to the basis plus basal endite. [Boxshall and Halsey, 2004]

Brachyura

An infra-order of decapod crustaceans. Used by Latrielle (1802) for the 'short tail' decapods, and now having the following restricted definition. Epistome always fused laterally with carapace and usually also medioanteriorly, pereiopod 1 chelate, 2-4 alike, abdomen reduced in size, bent under thorax. [Ingle, 1992]

Brachyuran crabs

Members of the infraorder Brachyura, in which all five pairs of thoracic legs are well developed.
(syn. true crabs) [Bliss, 1982]

Brain

(Taxon-specific: Order Notostraca) Main concentration of nreve tissue in head; consists of supraesophagael ganglion (protocerebrum and deutocerebrum) and, posterior to mouth, tritocerebrum (ganglion of antennal somite). Continues posteriorly as ladder-like ventral nerve cords. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Main concentration of nerve tissue in head. Consists basically of ganglion (supraesophageal ganglion = protocereberum + deutocerebrum) anterior to esophagus and ganglion (tritocerebrum) to side of or posterior to esophagus. Continues posteriorly as ladder-like ventral nerve cord. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) main concentration of nerve tissue in head. Consists basically of ganglion (supraesophageal ganglion = protocerebrum and deuterocerebrum) anterior to esophagus and ganglion (tritocerebrum = circumesophageal ganglion = ganglion of antennal somite) to each side of or posterior to esophagus. Continues posteriorly as ladder-like ventral nerve cord. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Main concentration of nerve tissue; consists of supraesophageal ganglion (protocerebrum, deuterocerebrum) and, posterior to mouth, tritocerebrum (ganglion of antennal somite). [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Main concentration of nerve tissue in cephalon. Connected with "eyes" by optic nerves and continues posteriorly to form subesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Main concentration of nerve tissue in cephalon. Consists of anterior protocerebrum, median deutocerebrum (ganglion of antennular somite), and, at some distance posterior to deutocerebrum, a tritocerebrum (ganglion of antennal somite). Surrounds esophagus and gives rise to pair of ventral nerve cords. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Main concentration of nerve tissue located above foregut in anterior region of head (cephalon); connected to ventral nerve cord by pair of circumesophageal commissures.
(syn. supraesophageal ganglion) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Main concentration of nerve tissue above (anterior to) esophagus. Continues posterior to esophagus as ventral nerve cord.
(syn. supraesophageal ganglion) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Supraesophageal ganglion. [Stachowitsch, 1992]

Branchia

Gills, usually thoracic. [Poore, 2004]
Respiratory organ (gill) associated with an appendage or with the body wall.
(pl. branchiae) [Perez Farfante and Kensley, 1997]
Thin-walled finger-like or leaf-like structure extending outward from limb or secondarily from side of body, functioning for respiration.
(syn. gill. [Special types are termed arthrobranchs, pleurobranchs, and podobranchs, depending on their pl) [Moore and McCormick, 1969]
Thin-walled, fingerlike or leaflike structure extending outward from appendage or secondarily from side of body, functioning in respiration.
(pl. branchiae) (syn. gill) [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Gill. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Coxal gill. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Respiratory structure on or modification (thin cuticle, folding, etc.) of pleopod for gas exchange. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Gill. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Gill. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Branchial plate, gill. [Stachowitsch, 1992]

Branchial

Pertaining to the gills. [Butler, T. H.]

Branchial apparatus

(Taxon-specific: Order Cumacea) Term applied to epipods of first maxilliped pair (or, in an alternate interpretation, to epipods and exopods). Modified for respiration, the posteriorly directed part extending into branchial cavity and bearing branchial lobules, the anteriorly directed part ("exopod") forming part of exhalant cephalon. [Stachowitsch, 1992]

Branchial carina

See: Carapace carina b [Martin, 2005]
See: Carapace carina b [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) On each side of carapace in shrimp-like (natantian) decapod, narrow, longitudinal ridge extending posteriorly from orbit over branchial region. [Stachowitsch, 1992]

Branchial cavity

See: Branchial chamber [Martin, 2005]
Space between thorax and lateral flap of carapace (branchiostegite) enclosing branchia or gills. [Poore, 2004]

Branchial chamber

A chamber limited primarily by the lateral folds of the carapace, the inner surface of which performs a respiratory function. [Holdich and Jones, 1983]
Area between body and carapace enclosing branchiae.
(syn. gill chamber) [McLaughlin, 1980]
Chamber between carapace and body wall (pleura) that contains gills in most decapods. [Brusca and Brusca, 2002]
On either side of the cephalothorax of shrimps, lobsters, crabs and certain other crustaceans; formed from a deep lateral fold of the carapace; house the gills. [Bliss, 1982]
Space between body and wall of carapace enclosing branchiae.
(syn. gill chamber) [Moore and McCormick, 1969]
The chamber formed by the lateral region of the carapace enclosing the gills. [Ingle, 1983]
(Taxon-specific: Order Cumacea) Space on each side of cephalothorax between body and inner wall of carapace. Contains posteriorly directed part of epipods of first maxillipeds. Closed posteriorly, with water entering anteriorly and exiting frontmedially via siphon. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Space on each side of head between body and inner wall of carapace. Epipods of maxillipeds extend into branchial chamber. Water enters chamber primarily at posteroventral margins of carapace and exits ventrally at bases of maxillipeds.
(syn. branchial cavity) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Lateral or dorsolateral space on each side of cephalothorax between body wall and carapace; encloses gills. In shrimp-like (natantian) decapod, water enters branchial chamber along posterior or ventral edges of carapace; in crab-like (brachyuran) decapod, it typically enters via afferent respiratory channels near bases of chelipeds.
(syn. gill chamber)
See: Epibranchial space, Hypobranchial space [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Area on ventral surface of abdomen (pleon) containing branchiae; may be covered by expanded pleopods or uropods. [Stachowitsch, 1992]

Branchial count

The number of gills and epipodites present on one side of the cephalothorax. [Hobbs, Hobbs, and Daniel 1977]

Branchial filament

(Taxon-specific: Subclass Copepoda) In parasitic copepod, one element in tuft-like aggregations of slender processes of abdomen. [Stachowitsch, 1992]

Branchial glands

masses of connective-tissue cells surrounding venous channels in branchiae and devoid of ducts. [Moore and McCormick, 1969]
Masses of connective-tissue cells without ducts surrounding venous channels in branchiae. [McLaughlin, 1980]

Branchial lobe

A boss located at the anteriomesial angle of the mesobranchial region on the carapace of certain crabs. [Chace and Hobbs, 1969]
(Taxon-specific: Order Cumacea) One in a series of respiratory projections along posteriorly directed part of epipods of first maxillipeds. Located in branchial chamber. (finger-like, lamelliform) (See also accessory lobule). [Stachowitsch, 1992]

Branchial plate

(Taxon-specific: Class Ostracoda) Enlarged, flattened modification of outer branch (exopod) of either mandible, maxillule, maxilla, or first thoracic limb. Bears long setae along margin and maintains water circulation within carapace.
(syn. vibratory plate, respiratory plate) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Flat setose epipod, used to circulate water through the domicilium.
(syn. vibratory plate) [Cohen, Peterson, and Maddocks, in press]

Branchial region

See: Carapace region c [Martin, 2005]
See: Carapace regions c [McLaughlin, 1980]
Area of the carapace overlying the branchial cavity. [Perez Farfante and Kensley, 1997]
Paired regions of dorsal carapace between hepatic regions in front posterior margin behind, sometimes bearing branchial spine(s), defined laterally in crabs by posterolateral margin. [Poore, 2004]
Portion of the carapace overlying the branchial cavity. [Butler, T. H.]
The portion of the carapace overlying the branchial cavity, in the true crabs comprising the epibranchial, mesobranchial, and metabranchial regions and the branchial lobe. [Chace and Hobbs, 1969]
(Taxon-specific: Order Cumacea) One of two relatively larger lateral regions of carapace overlying branchial chamber.
(syn. branchial area) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) One of two relatively large, lateral regions of carapace overlying gills (branchiae). May be subdivided (from anterior to posterior) into epibranchial, mesobranchial, and metabranchial regions/ lobes/areas. [Stachowitsch, 1992]

Branchiocardiac carina

See: Carapace carina c [Martin, 2005]
See: Carapace carinae c [McLaughlin, 1980]
Ridge extending along posterodorsal limit of branchiostegite (Fig. 2A). [Perez Farfante and Kensley, 1997]
(Taxon-specific: Order Decapoda) On each side of carapace, narrow ridge separating branchial region from cardiac region. [Stachowitsch, 1992]

Branchiocardiac groove

See: Carapace groove b [Martin, 2005]
See: Carapace grooves b [McLaughlin, 1980]
Groove separating branchial and cardiac regions. [Williams, 1984]
Line along dorsal limit of branchiostegite.
(syn. branchiocardiac ridge) [Poore, 2004]
(Taxon-specific: Order Decapoda) On each side of carapace, oblique groove separating branchial and cardiac regions. Considered to represent former transverse border between two cephalic somites. May also refer to pair of grooves connecting cervical and postcervical grooves or extending posteriorly from post-cervical groove. [Stachowitsch, 1992]

Branchiocardiac sulcus

Groove extending along dorsal limit of branchiostegite, running parallel to branchiocardiac carina. [Perez Farfante and Kensley, 1997]

Branchiostegal area

Part of carapace extending laterally and downward over branchiae. [Moore and McCormick, 1969]
Part of carapace extending laterally and ventrally over branchiae. [McLaughlin, 1980]

Branchiostegal carina

Longitudinal ridge extending along anteroventral part of carapace, usually continuous with branchiostegal spine. [Perez Farfante and Kensley, 1997]

Branchiostegal spine

See: Carapace spine b [Martin, 2005]
See: Carapace spines b [McLaughlin, 1980]
A short spine located on or near the anterior margin of the carapace, ventral to the antennal spine in the shrimps; in crayfishes, immediately ventral to the anterior extremity of the cervical groove. [Hobbs, Hobbs, and Daniel 1977]
A short spine on or near the anterior margin of the carapace of some shrimps ventral to the antennal spine and dorsal to the anterolateral angle of the carapace. [Chace and Hobbs, 1969]
Short spine on or near the anterior margin of the carapace ventral to the antennal spine and dorsal to the anteroventral angle of the carapace (Fig. 2A). [Perez Farfante and Kensley, 1997]
Short spine situated on or near anterior margin of carapace, ventral to antennal spine in shrimps; in crayfishes, located immediately ventral to anterior extremity of cervical groove (see Fig. 13). [Hobbs and Jass, 1988]
Spine on anterior edge of carapace, or near it, immediately below branchiostegal groove (Fig. 2). [Williams, 1984]
Spine on or near anterolateral margin of the carapace of some shrimps, ventral to antennal spine and dorsal to pterygostomian spine. [Butler, T. H.]
(Taxon-specific: Order Decapoda) Anteriorly directed, spine-like projection on branchial region on each side of carapace in shrimp-like (natantian) decapod; located at anterior margin, below branchiostegal groove and between antennal and pterygostomial spines. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Spine. [Stachowitsch, 1992]

Branchiostegal sulcus

Groove often accompanying branchiostegal carina, located on the anteroventral part of the carapace. [Perez Farfante and Kensley, 1997]

Branchiostegal-hepatic carina

Longitudinal ridge consisting of the fusion of the branchiostegal and hepatic carinae. [Perez Farfante and Kensley, 1997]

Branchiostegite

Expanded dorsal and lateral branchial region of carapace. [McLaughlin, 1980]
Expanded ventro-lateral part of the carapace covering the gills (Fig. 2A). [Perez Farfante and Kensley, 1997]
Expanded ventrolateral part of carapace covering gills. [Poore, 2004]
Part of carapace extending over top and side of branchial chamber. [Moore and McCormick, 1969]
Part of carapace not coalesced ventrally with thoracic somites, but overhanging on each side as covering for gill chamber. [Williams, 1984]
The anterior and lateral margins of the carapace extending ventrally on either side. [Ingle, 1983]
(Taxon-specific: Order Decapoda) Lateral or dorsolateral part of carapace extending over gills and forming outer wall of branchial chamber. [Stachowitsch, 1992]

Branchiostegites

The anterior and lateral margins of the carapace extend ventrally on either side forming the walls of the cephalothorax and enclosing the branchial chambers (Fig. 1). [Warner, 1977]

Bristle

Indefinite term for short, stiff seta or spinule. [Butler, T. H.]

Brood chamber

(Taxon-specific: Order Cumacea) In female, chamber formed on ventral surface of pereon by oostegites on last (third) maxillipeds and on first three pereopod pairs.
(syn. brood pouch, marsupium) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) In female, space between thoracopods and carapace in which eggs are brooded. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) In female rhizocephalan, pouch-like structure projecting from body of host; contains eggs and seminal receptacle and serves as site of attachment of male. May also refer to brood pouch of ascothoracican.
(syn. externa) [Stachowitsch, 1992]

Brood plate

(Taxon-specific: Order Amphipoda) Oostegite. [Stachowitsch, 1992]

Brood pouch

(Taxon-specific: Order Tanaidacea) Marsupium. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) In female, chamber formed on ventral surface of pereon by oostegites on second to fifth pereopods.
(syn. marsupium) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Chamber formed on ventral surface of pereon in female by three to five pairs of oostegites.
(syn. brood chamber, marsupium) [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Marsupium. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) An expanded region of the female domicilium, usually posterior, for protecting developing eggs and instars. [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Order Thermosbaenacea) In female, dorsal chamber between thorax and carapace. Serves to brood eggs.
(syn. marsupium) [Stachowitsch, 1992]

Brood sac

A pouch formed from either one or two oostegites. [Holdich and Jones, 1983]

Brooding female

An adult female with fully extended oostegites on the coxae. In specimens from deep-sea samples, the developing embryos are often lost during sample processing, so it is generally not possible to tell whether the female was in fact brooding embryos, or whether she released the young before sampling. [Wilson, 1989]

Broom seta

A sensory seta that has a distinctly articulated pedestal, and two distal rows of long, extremely thin setules. It may be found on the antennulae or any of the pereopods. [Wilson, 1989]

Brush

Clump or band of setae or spinules, usually on distal flexor margin of propodus of fifth pereiopod; used by shrimp for grooming. [Butler, T. H.]

Brush-shaped organ

(Taxon-specific: Class Ostracoda) Rudimentary third pair of thoracopods (ninth paired appendage of body). Consists of basal part (stem) bearing distal cluster of hairs. Typically restricted to male and considered to be sensory.
(syn. brush-like structure) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Small pair of lobes bearing numerous fine setae; found between the fifth limbs in males of most Cytherocopina and some Cypridocopina; might represent vestigial appendages. [Cohen, Peterson, and Maddocks, in press]

Buccal cavern

Space, especially in crabs, enclosing the mouthparts and more or less covered by third maxillipeds, defined anteriorly by epistome and laterally by pterygostomial region, sometimes by ridges.
(syn. buccal frame) [Poore, 2004]

Buccal cavity

Cavity on ventral surface of body in which mouth parts are situated; bounded anteriorly by epistome, laterally by free edges of carapace. Within this "frame" lie the mouth parts, which in most Brachyura are covered by operculiform third maxillipeds. [Williams, 1984]
Hollow space on ventral side of body containing mouth parts, in Malacostraca bounded by epistome in front and free edges of carapace on sides. [Moore and McCormick, 1969]
The area on the ventral surface of the carapace in which the mouth parts are situated. Bounded anteriorly by the epistome, laterally by the inner margin of the pterygostomial region and posteriorly by the anterior margin of the first thoracic sternite. [Ingle, 1983]
(Taxon-specific: Class Malacostraca) Area of cephalon containing mouthparts; bounded by epistome anteriorly and free margins of carapace laterally. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) On underside of head, cavity in which mouthparts (labrum, mandibles, maxillules, maxillae, maxillipeds, labium) are located. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) In front of mouth, chamber formed by lip-like extensions of proboscis margins. Contains mandibles. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) In parasitic copepod, term applied to space formed around mouth by prolonged upper lip (labrum) and lower lip (labium). (See also mouth cone). [Stachowitsch, 1992]

Buccal frame

structure of brachyuran decapods enclosing mouth parts, its sides formed by free anterolateral edges of carapace, its front delimited by epistome, and commonly closed by operculiform third maxillipeds. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) In crab-like (brachyuran) decapod, well-defined, frame-like depression on underside of head; contains mouthparts (labrum, mandibles, maxillules, maxillae, maxillipeds, labium) and may be covered by expanded (operculiform) maxillipeds. (quadrate, triangular).
See: Endostome [Stachowitsch, 1992]
(Taxon-specific: Infraorder Brachyura) Structural region of cephalon enclosing mouthparts. [McLaughlin, 1980]

Buccal groove

(Taxon-specific: Order Decapoda) See: Carapace grooves c [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) On each side of carapace, transverse groove behind antennal spine; connects gastroorbital and antennal grooves. [Stachowitsch, 1992]

Bud

(Taxon-specific: Subclass Copepoda) The earliest step of a developing limb; a limb bud does not articulate with its somite and bear setae including at least the crown group of terminal setae. A limb bud often is considered functionless on immature stages although limb 6 of podopleans is a bud which covers the genital opening of the adult male (see transformed limb and secondary bud). [Ferrari and Dahms, in press]

Bulb

(Taxon-specific: Class Ostracoda) Type of valve sculpture: relatively large, subspherical projection. [Stachowitsch, 1992]

Bulla

(Taxon-specific: Subclass Copepoda) A small, chitinous anchor-like structure fused to the tips of the maxillary arms in lernaeopodid copepods, that is embedded in the surface of the host fish to serve as an anchor. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) In parasitic copepod, attachment disc formed at fused end of both arm-like maxillae. (club-shaped, elliptical, spherical).
(syn. button) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Type of valve sculpture: tubercle-like projection whose summit is elongated into a transverse or radial direction. May be considered to be type of verruca. [Stachowitsch, 1992]

CB

The junction between the coxa and the basi-ischium (Fig. 12). [Warner, 1977]

CP

The junction between the carpus and the propodus (Fig. 12). [Warner, 1977]

Calamus

(Taxon-specific: Subclass Copepoda) The main claw on the apex of the basis of the maxilla of some siphonostomatoids. [Boxshall and Halsey, 2004]

Calathus

See Optic Calathus. [Perez Farfante and Kensley, 1997]

Calcar

(Taxon-specific: Order Anostraca) Spur-like process on distal segment of antenna. (one-half as long/one-eighth or less as long as basal segment of antenna). [Stachowitsch, 1992]

Calceolus

Complex sensory filaments on antennules of some amphipods. [Moore and McCormick, 1969]
(Taxon-specific: Order Amphipoda) Complex sensory filaments on antennules.
(pl. calceoli) [McLaughlin, 1980]
(Taxon-specific: Order Amphipoda) One in a series of club-shaped sensory projections on antennules and antennae. More common in male.
See: Aesthetascs [Stachowitsch, 1992]

Calcified inner lamella

(Taxon-specific: Class Ostracoda) Calcified part of the inner (medial) lamella of valve margin. [Cohen, Peterson, and Maddocks, in press]

Calyptopis

First larval stage following the nauplius stage in euphausids, corresponding roughly to the the protozoea stage. [Brusca and Brusca, 2002]
Larval stage of euphausiids. There are three successive calyptopes, distinguished by the increasing degree of development of the abdomen. [Mauchline, 1984]
Third larval stage in euphausiaceans, characterized by differentiation of abdomen and appearance of compound eyes. [Moore and McCormick, 1969]
Third larval stage, characterized by differentiation of abdomen and appearance of compound eyes (Euphausiacea); see also zoea. [McLaughlin, 1980]
(Taxon-specific: Order Euphausiacea) Third of several larval stages (nauplius, metanauplius, calyptopis, furcilia). Characterized by development of carapace, elongation of abdomen, differentiation of somites, and development of eyes under carapace.
See: Cyrtopia [Stachowitsch, 1992]

Canna

(Taxon-specific: Subclass Copepoda) The armature element representing the basal endite of the maxilla of some siphonostomatoids. [Boxshall and Halsey, 2004]

Caperation

(Taxon-specific: Class Ostracoda) Type of valve sculpture: fine wrinkle. [Stachowitsch, 1992]

Capitate

Enlarged or globular at end. [AHD]

Capitulum

In pedunculate cirripeds portion of carapace enclosing trophic structures, commonly armored by calcareous plates. [Moore and McCormick, 1969]
Portion of carapace enclosing body, commonly protected by calcareous plates (lepadomorph cirripeds); or anterior prominence in complex tooth and socket hingement (Ostracoda). [McLaughlin, 1980]
(Taxon-specific: Subclass Cirripedia) In stalked barnacle, one of two external divisions of body (capitulum, peduncle). Consists of mantle and associated plates enclosing body. [Stachowitsch, 1992]

Carapace

Entire animal, right appendages omitted, dorsal view, based on Munida. [Baba, 2005]
(Figure only.) [Baba, 2005]
Carapace, spines, based on Munida. [Baba, 2005]
(Figure only.) [Baba, 2005]
"Head Shield" cuticular structure arising from posterior margin of cephalon, extending anteriorly and posteriorly, and covering the cephalothoracic somites of the body (Fig. 1). [Perez Farfante and Kensley, 1997]
"Shield" (exoskeleton) overlying cephalothoracic somites of body (see Figs. 13,14) [Hobbs and Jass, 1988]
'Head shield" covering the cephalothoracic somites of the body. [Butler, T. H.]
A more expansive structure than the head shield (cephalic shield) , comprising the head shield and a large fold of the exoskeleton that probably arises (primitively) from the maxillary somite. [Brusca and Brusca, 2002]
A sheet of cuticle extending back from the head to enclose the dorsal and lateral parts of the thorax; the 'shell' of a crab (Fig. 1). [Warner, 1977]
A shield that covers the head and thorax. [Mauchline, 1984]
an extension of the exoskeleton which covers and fuses with the head and the first two thoracic somites. [Holdich and Jones, 1983]
Cuticular, usually calcified, structure arising from posterior margin of cephalon, extending anteriorly and posteriorly, often covering head and thorax (cf. Eucarida); also fold of integument extending from maxillary segment, forming bivalved shell of cyprid larvae and of ascothoracicans and mantle of other cirripedia; mantle usually with calcified plates in thoracicans. [McLaughlin, 1980]
Cuticular, varyingly calcified structure comprising cephalic shield and fold of integument arising from posterior border of maxillary somite extending over trunk, usually covering it laterally as well as dorsally; commonly fused to one or more thoracic somites and in may forms having mid-dorsal hinge. [Moore and McCormick, 1969]
Shield arising from posterior margin of head and comprising lateral extensions of thoracic somites covering all or most of cephalothorax. [Poore, 2004]
The "head shield" covering the cephalothoracic somites of the body. [Chace and Hobbs, 1969]
The "head shield" overlying the cephalothoracic somites of the body. [Hobbs, Hobbs, and Daniel 1977]
The exoskeleton that covers the dorsal and ventro-lateral portions of the cephalothorax. [Ingle, 1980]
The portion of the hard exoskeleton, or shell, that covers all or part of the body of many crustaceans; in shrimps, lobsters, and crabs, the carapace covers the head and thorax. [Bliss, 1982]
(Taxon-specific: Order Cladocera) Single-piece (univalved) shield which, if fully developed, covers only posterior part of body (trunk). Laterally compressed, with ventral gape, and therefore occasionally described as bivalved (i.e., consisting of two "valves" ). (angular, circular, elongate, oval, ovate, ovoid, spherical, subcircular, subquadrate; laterally compressed, thick-bodied; with/without carapace spine, with/without crest, narrowed and prolonged/not narrowed and prolonged posteriorly into short tube, anterior portion swollen/not swollen, with/without projection on anteroventral margin, ventral margin smooth/with fine spines, dorsal margin smooth/serrate; sculpture: reticulated, smooth; longitudinally, obliquely, transversely striated; with/without hairs, with polygonal or rhomboid markings).
(syn. shell) [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Large broad shield covering dorsal surface of head, thorax, and anterior part of abdomen. Consists of single element (univalve) and is emarginated (notch, sinus) posteriorly. Bears median eye, compound eyes, and dorsal organ anteriorly and is sculptured by median keel and transverse mandibular and cervical grooves.
(syn. dorsal shield) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Bivalved, laterally compressed shield typically enclosed entire body; consists of two valves with dorsal hinge line, although occasionally interpreted as representing a single continuous element. Joined to body by ligament and pair of adductor muscles in head region. (broadly oval, compressed, globose = globular, oblong, ovate, subovate, subrectangular, subspherical, swollen, thick and globose, thin and pellucid; with/without growth lines; with/without umbones; with/without keel; sculpture: polygonal, punctate, reticulate, with dendritic or radial grooves, with striae).
(syn. shell) [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Large, shield-like structure covering head and three to six thoracic somites. Extends laterally to enclose branchial chamber. Regionated to form anterior pseudorostrum, frontal lobe, ocular lobe, as well as branchial and cardiac regions. (inflated, laterally compressed; dorsal outline: straight, arched, with slight undulations; with/without lateral horns; smooth, sculptured: hairy, rugose, with denticles, with median/lateral carina, with longitudinal depressions, with dorsal crest: serrate, smooth, with teeth). [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Shield-like structure covering head and first two thoracic segments (thoracomeres). Extends laterally to enclose branchial chamber.
See: Cephalothorax [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Large, shield-like cuticular structure covering cephalothorax; bears rostrum anteriorly and is typically regionated and sculptured with various carinae, grooves, spines, and teeth. Encloses gill-bearing bases of thoracopods and thus forms branchial chambers. (general form: cylindrical, compressed, depressed; shape: convex, circular, globular, hemispherical, hexagonal, octagonal, orbicular, oval, ovate triangular, pentagonal, polygonal, pyriform, quadrilateral, rectangular, subcircular, subcylindrical, subglobose, subhexagonal, suborbicular, subovoid, subpenta-gonal, subquadrate, subquadrilateral, sub-triangular, transversely oval, tumid; surface: areolated, carinate, eroded, glabrous, granulate, nodular, nodulose, plicate, polished, pubescent, punctuate, with rugae, smooth, squamose, tuberculate, wrinkled). [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Shield-like structure coving head and most of thorax. Typically fused to first three thoracic segments (thoracomeres) and typically bearing rostrum. (with/without rostrum; undecorated, ornamented: spinose, with keels; posterior margin: indented, produced into spines, with lobes) (See also cervical sulcus). [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Shield-like cuticular structure covering cephalon (except for anterior acron and antennular somite) as well as first four thoracic somites (thoracomeres); overlaps but does not enclose bases of first five thoracopods. Broad, flattened, and typically sculptured with various carinae and grooves. Bears rostrum anteriorly. (with/without carinae; anterolateral corners: armed, unarmed, rounded). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Large shield covering thorax, posterior part of head, and anterior part of abdomen. Laterally compressed and therefore often described as being bivalved (although no dorsal hinge is present). Two halves of carapace can be drawn toward each other by carapace adductor muscle. Bears rostral plate anteriorly. (elliptical and posterodorsally truncate, subtriangular and posteriorly acuminate; smooth, with polygonal ornamentation). [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Dorsoventrally flattened, shield-like structure covering head and first thoracic somite (thoracomere); characterized by pair of posterolateral wing-like extensions (alae). Bears pair of compound eyes dorsolaterally and set of median nauplius eyes. (circular, cordate, elliptical, trifoliate). [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Mantle. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Lateral outfolds of dorsal epithelium and cuticle, bivalved and enveloping the entire body. [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Class Ostracoda) Shell-like outer covering; consists of pair of valves joined dorsally by hinge and entirely enclosing body. (calcareous, uncalcified; ornate, smooth; amplete, postplete, preplete). [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Shield-like structure fused to and covering head and first thoracic somite (thoracomere). Extends posteriorly and laterally to cover additional thoracomeres. Serves in respiration and forms brood pouch in female. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Shield-like, relatively thin structure fused to thoracic somites and covering cephalothorax. Does not enclose gill-bearing bases of thoracopods. Typically bears cervical groove. (with/without rostrum). [Stachowitsch, 1992]

Carapace angles

In Leaiidae (Conchostraca), angle made by straight dorsal margin with anterior rib (a) and with posterior rib (b); these angles may have utility in tracing evolutionary development and in stratigraphic zonation. [Moore and McCormick, 1969]
(Taxon-specific: Order Diplostraca) Intersection of straight and dorsal margin by anterior rib (alpha) and posterior rib (beta). [McLaughlin, 1980]

Carapace carina

Narrow ridge on surface of carapace (cf. decapod carapace and stomatopod integumental ornamentation). [McLaughlin, 1980]
Narrow ridge variously located on surface of decapoda carapace — named types:
a) antennal. Narrow ridge extending backward from antennal spine.
b) branchial. Narrow ridge extending backward from orbit over branchial region.
c) branchialcardiac. Narrow ridge marking off branchial from cardiac regions of carapace.
d) gastroorbital. Narrow ridge extending backward from supraorbital spine.
e) lateral. Narrow ridge on side margin of carapace.
f) orbital. Narrow ridge on margin of orbit.
g) posterior. Transverse narrow ridge in front of carapace marginal groove.
h) postorbital. Narrow ridge slightly behind orbital margin and parallel to it.
i) postrostral. Narrow ridge behind rostrum extending along dorsal mid-line of carapace.
j) rostral. Longitudinal narrow ridge continuous with lateral margin of rostrum.
k) subhepatic. Narrow ridge extending backward from branchiostegal spine.
l) submedian. Narrow ridge on either side of postrostral carina and parallel to it; may join rostral carina.
m) supraorbital.
See: Gastroorbital carina [Moore and McCormick, 1969]

Carapace carinae

(Taxon-specific: Order Decapoda) (a) antennal. Extending posteriorly from antennal spine.
(b) branchial. Extending posteriorly from orbit over branchial region.
(c) branchiocardiac. Dividing branchial from cardiac region.
(d) gastroorbital. Extending posteriorly from supraorbital spine; syn., supraorbital.
(e) lateral. On lateral margin of carapace.
(f) orbital. On margin of orbit.
(g) posterior. Transverse ridge anterior to marginal groove.
(h) postorbital. Slightly posterior and parallel to orbital margin.
(i) postrostral. Posterior to rostrum along dorsal midline.
(j) rostral. Continuous with lateral margin of rostrum.
(k) subhepatic. Extending posteriorly from branchiostegal spine.
(l) submedian. On either side of, and parallel to, postrostral carina, sometimes joining rostral carina.
(m) supraorbital. See gastroorbital. [McLaughlin, 1980]

Carapace costae

Closely spaced radial ridges, grading from fine to coarse, that become obsolete near umbo and do not cross it (=radial lirae, radial riblets, accessory ribs) (e.g., Conchostraca, especially Estheriellidae, in which valves generally have more than 5 costae). [Moore and McCormick, 1969]
(Taxon-specific: Order Diplostraca) Closely spaced radial ridges, grading from fine to coarse, not crossing to umbo.
(syn. radial lirae) [McLaughlin, 1980]

Carapace costellae

Fine radial ridges that run from ventral margin to and across umbo, and are usually numerous on any given valve (e.g. Conchostraca). [Moore and McCormick, 1969]
(Taxon-specific: Order Diplostraca) Fine radial ridges extending from ventral margin across umbo. [McLaughlin, 1980]

Carapace groove

Furrow on surface of decapod, generally dorsal — named types:
a) antennal. Furrow on carapace extending backward from vicinity of antennal spine.
b) branchiocardiac. Oblique furrow approximately in middle of posterior half of each side of carapace, separating branchial and cardiac regions and reaching dorsomedian part of carapace well behind cervical or postcervical grooves; may be longitudinal, connecting cervical and postcervical grooves, or extending backward from submedian point on postcervical groove.
c) cervical. Transverse furrow in median part of carapace between gastric and cardiac regions, curving forward toward antennal spine.
d) gastroorbital. Short longitudinal furrow branching from cervical groove at level of orbit and running toward it.
e) hepatic. Short longitudinal furrow connecting cervical with postcervical and branchiocardiac grooves, more or less continuing antennal groove.
f) inferior. Transverse furrow extending from junction or hepatic and cervical grooves toward side margin of carapace, more or less continuous with cervical groove.
g) marginal. Furrow close to posterior edge of carapace and parallel to it.
h) postcephalic. one of three transverse furrows on carapace of many fossil decapods.
i) postcervical. Furrow located behind cervical groove and parallel to it, dividing cardiac region into two parts.
j) submedian. Longitudinal furrow in submedian dorsal part of carapace closely adjacent to post-rostral carina. [Moore and McCormick, 1969]

Carapace grooves

(Taxon-specific: Order Decapoda) (a) antennal. Extending posteriorly from vicinity of antennal spine.
(b) branchiocardiac. Oblique groove approximately in middle of posterior half on each side of carapace, separating branchial and cardiac regions and reaching dorsomedian part well posterior to cervical or postcervical grooves; sometimes longitudinal, connecting cervical and postvcervical grooves or extending posteriorly from submedian point on postcervical groove.
(c) buccal. Transverse groove crossing mandibular elevation behind antennal spine, connecting gastroorbital and antennal grooves.
(d) cervical. Transverse groove medially between gastric and cardiac regions, curving toward antennal spine; syn., cervical suture, cervical furrow.
(e) dorsomedian. Longitudinal groove extending from tip of rostrum to posterior carapace margin dorsomedially.
(f) gastroorbital. Short, longitudinal groove branching from cervical groove at level of orbit and directed toward it.
(g) hepatic. Short, longitudinal groove connecting cervical with postcervical and branchiocardiac grooves, more or less continuous with antennal groove.
(h) inferior. Extending from junction of hepatic and cervical grooves toward lateral margin, more or less continuous with cervical groove.
(i) intercervical. Oblique groove connecting postcervical and cervical grooves.
(j) intestinal. Short, transverse groove in median part of posterior carapace, interrupted by intestinal tubercle.
(k) marginal. Close to, and parallel with, posterior margin.
(l) parabranchial. Groove below, behind and almost parallel with branchiocardiac and postcervical grooves, joining latter in lower part.
(m) postcephalic. One of three transverse furrows on carapace of many fossils.
(n) postcervical. Posterior to, and parallel with, cervical groove, bisecting cardiac region.
(o) sellar. Short transverse groove dorsally anterior tp cervical groove.
(p) submedian. Longitudinal groove in submedian dorsal part, contiguous with postrostal carina.
(q) urogastric. Short transverse groove in median or submedian region posterior to postcervical groove, sometimes joining upper part of postcervical groove. [McLaughlin, 1980]

Carapace growth line

(Taxon-specific: Order Diplostraca) Peripheral margin of successive membranes added to shell during each molt. [Moore and McCormick, 1969]

Carapace horn

Anterodorsal termination of carapace valves in some Archaeostraca; may be indurated (e.g., Ceratiocaris) or produced into long process (e.g., Caryocaris). [Moore and McCormick, 1969]

Carapace length

In shrimps, distance from the posterior margin of orbit to midcaudodorsal margin of carapace; in crayfishes, distance from tip of rostrum to midcaudodorsal margin of carapace (see Fig. 14). [Hobbs and Jass, 1988]
In shrimps, the distance from the posterior margin of the orbit to the mid-caudodorsal margin of the carapace; in crayfishes, the distance from the tip of the rostrum to the mid-caudodorsal margin of the carapace. [Hobbs, Hobbs, and Daniel 1977]

Carapace lirae

(Taxon-specific: Order Diplostraca) Linear concentric edges parallel to and between growth lines. [McLaughlin, 1980]
(Taxon-specific: Order Diplostraca) Raised, linear, fine concentric ridges parallel to growth lines and occupying an interspace. [Moore and McCormick, 1969]

Carapace region

Differentiated portion of decapod carapace surface distinguished in descriptions and used in classification — named types:
a) antennal. Anterior marginal part of carapace bordering orbital region laterally and also touching hepatic, pterygostomial, and, in some forms, frontal region.
b) anterolateral. Lateral part of carapace bordering subhepatic or hepatic regions.
c) branchial. Lateral part of carapace behind pterygostomial region and overlying branchiae, divided by some authors into epibranchial, mesobranchial, and metabranchial subregions.
d) cardiac. Median part of carapace behind cervical groove or suture, between urogastric and intestinal areas.
e) frontal. Anteromedian part of carapace including rostrum and area behind it.
f) gastric. Median part of carapace in front of cervical groove and behind frontal region; divided by some authors into epigastric, mesogastric, metagastric, protogastric, and urogastric subregions.
g) hepatic. Part of carapace which may touch antennal, cardiac, and pterygostomial regions.
h) intestinal. Short transverse part of carapace behind cardiac region, designated by some as posterior cardiac lobe.
i) jugal. See: Pterygostomial region
j) orbital. Part of carapace behind eyes, bordered by frontal and antennal regions.
k) pterygostomial. Anterolateral part of carapace on ventral surface located on opposite sides of buccal cavity.
l) subhepatic. Part of carapace below hepatic region and extending below lateral edge of latter.
(syn. carapace area) [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) Differentiated portion of carapace surface.
See: Carapace regions [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) One of numerous, more or less clearly delimited and elevated subdivisions of carapace. According to position or underlying internal organs, as well as according to group, one may distinguish antennal, anterolateral, branchial, cardiac, epibranchial, epigastric, frontal, gastric, hepatic, intestinal, mesobranchial, mesogas-tric metabranchial, metagastric, orbital, pos-terolateral, protogastric, pterygostomial, subhepatic, and urogastric regions. [Stachowitsch, 1992]

Carapace regions

(Taxon-specific: Order Decapoda) (a) antennal. Anterior marginal part bordering orbital region laterally, adjoining hepatic, pterygostomial, and occasionally also frontal regions.
(b) anterolateral. Lateral part bordering subhepatic or hepatic regions.
(c) branchial. Lateral part posterior to ptergostomial region, overlying branchiae; epibranchial, mesobranchial, and metabranchial lobes or areas sometimes distinguished.
(d) cardiac. Median part posterior to cervical groove between urogastric and intestinal regions.
(e) frontal. Anteromedian part including rostrum and region behind it.
(f) gastric. Median part posterior to cervical groove and posterior to frontal region; sometimes epigastric, mesogastric, metagastric, protogastric, and urogastric (genital) areas distinguished.
(g) hepatic. Part adjoining antennal, cardiac, and pterygostomial regions.
(h) intestinal. Short traverse part posterior to cardiac region; sometimes referred to as posterior cardiac lobe.
(i) jugal. See pterygostomial region.
(j) orbital. Part posterior to eyes bordered by frontal and antennal regions.
(k) pterygostomial. Anterolateral part on ventral surface located on opposite sides of buccal cavity; syn., jugal region, pterygostome.
(l) subhepatic. Part on ventral surface below hepatic region, bounded by pterygostomial and suborbital regions.
(m) suborbital. Part on anteroventral surface beneath orbit. [McLaughlin, 1980]

Carapace spine

Sharp projection of carapace important for classification — chief types:
a) antennal. Spine on front margin of carapace slightly below orbit.
b) branchiostegal. Spine on front margin of carapace or slightly behind it about halfway between antennal and pterygostomial spines.
c) hepatic. Spine in hepatic region of carapace below lower branch of cervical groove and behind it.
d) infraorbital. Spine on lower angle of orbit.
e) postorbital. Spine at moderate distance behind middle of orbit.
f) postrostral. Dorsomedian spine immediately behind rostrum.
g) pterygostomial. Spine on anterolateral angle of carapace.
h) suborbital. Spine at moderate distance below middle of orbit and slightly beneath it.
i) supraorbital. Spine at moderate distance obliquely behind and above orbit (may be placed at postorbital carina). [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) Large, posteriorly directed, spine-like structure formed by posterodorsal extension of carapace. Relative length may be of taxonomic importance.
(syn. apical spine, posterior spine, shell spine) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Sharp projection from carapace.
See: Carapace spines [McLaughlin, 1980]

Carapace spines

(Taxon-specific: Order Decapoda) (a) antennal. On anterior margin slightly below orbit.
(b) branchiostegal. On or clsoe to anterior margin medially between antennal and pterygostomial spines.
(c) hepatic. Below and posterior to lower branch of cervical groove.
(d) infraorbital. On lower angle of orbit.
(e) postorbital. At moderate distance posterior to middle of orbit.
(f) postrostral. Immediately posterior to rostrum.
(g) pterygostomial. On anterolateral angle.
(h) suborbital. Slightly below and posterior to middle of orbit.
(i) supraorbital. At moderate distance obliquely behind and above orbit; somtimes on postorbital carina. [McLaughlin, 1980]

Carapace teeth

(Taxon-specific: Order Decapoda) (a) cardiac. On midline of carapace just posterior to cervical groove.
(b) gastric. On midline of carapace immediately anterior to cervical groove.
(c) lateral. On lateral margin of carapace; anterolateral, mediolateral, and posterolateral teeth distinguished.
(d) orbital. On orbital margin.
(e) posterior. On midline of carapace between posterior margin and marginal groove.
(f) pregastric. On midline of carapace between gastric tooth and rostrum.
(g) rostral. On rostrum, either single or multiple; upper, lower, and lateral teeth distinguished. [McLaughlin, 1980]

Carapace tooth

Generally blunt projection of carapace, often broader than spine.
See: Carapace teeth, Stomatopod integumental ornamentation [McLaughlin, 1980]
Small sharp spinous projection in varied locations — named types:
a) cardiac. Tooth on mid-line of carapace just behind cervical groove.
b) gastric. Tooth on mid-line of carapace just in front of cervical groove.
c) lateral. Tooth placed on lateral margin of carapace (includes anterolateral, mediolateral, posterolateral teeth).
d) orbital. Tooth on orbital margin.
e) posterior. Tooth on mid-line of carapace just in front of posterior margin between it and marginal groove.
f) pregastric. Tooth on mid-line of carapace between gastric tooth and rostrum.
g) rostral. Tooth on rostrum; may be single (e.g., scyllarid palinurans) or multiple and classified as upper, lower or lateral (e.g., nephropid astacideans and natantian crabs). [Moore and McCormick, 1969]

Carcinisation

Tendency for decapods to evolve towards a crab-like form. [Poore, 2004]

Cardiac

A median region of the carapace, between the gastric and intestinal regions. [Poore, 2004]

Cardiac notch

Indentation on posterior margin of carapace (e.g., some Alpheidae).
(syn. cardiac incision) [Moore and McCormick, 1969]
Indentation on posterior margin of carapace. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) In shrimp-like (natantian) decapod, notch on posterior margin of carapace. [Stachowitsch, 1992]

Cardiac region

See: Carapace region d [Martin, 2005]
See: Carapace regions d [McLaughlin, 1980]
Dorsolateral region of carapace bounded anteriorly by gastric region and laterally by branchial regions. [Butler, T. H.]
The dorsomedian area on the carapace bounded anteriorly by the gastric region, laterally by the branchial regions, and (in the crabs) posteriorly by the intestinal region. This area is often very narrow in the crayfishes and commonly called the areola. [Chace and Hobbs, 1969]
The region on the dorsal surface of the carapace bounded by parts or the margins of the urogastric, mesobranchial, metabranchial and intestinal regions. [Ingle, 1983]
(Taxon-specific: Order Cumacea) Unpaired median region in posterior half of carapace; overlies anterior region of heart. (See also branchial region). [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Relatively large, unpaired median region in posterior half of carapace; overlies heart. Adjoined anteriorly by gastric, posteriorly by intestinal, and laterally by branchial regions. [Stachowitsch, 1992]

Cardiac stomach

Anterior region of the decapod foregut. [Brusca and Brusca, 2002]
(Taxon-specific: Order Decapoda) Anterior and larger cuticle-lined division of stomach; separated from smaller posterior pyloric stomach by cardiopyloric valve and characterized by variously developed grinding apparatus (gastric mill). [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Anterior and larger division of stomach occupying most of head (cephalon). Separated from smaller posterior pyloric stomach by filtering apparatus; contains only small pairs of plates (ossicles). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Stomach. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Anterior and larger division of stomach; separated from smaller posterior pyloric stomach by cardiopyloric valve. Serves to grind food. (with/without denticles). [Stachowitsch, 1992]

Cardiac tooth

See: Carapace tooth a [Martin, 2005]
See: Carapace teeth a [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) On midline of carapace, tooth-like projection in cardiac region just posterior to cervical groove. [Stachowitsch, 1992]

Cardial sulcus

(Taxon-specific: Order Mysida) Transverse groove across posterior region of carapace at level of heart. (See also cervical sulcus). [Stachowitsch, 1992]

Cardiopyloric valve

(Taxon-specific: Order Decapoda) In digestive tract, valve-like structure between anterior cardiac stomach and posterior pyloric stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) In digestive tract, valve-like structure between anterior cardiac stomach and posterior pyloric stomach. [Stachowitsch, 1992]

Cardo

Basal segment of maxillula articulating with head. [Moore and McCormick, 1969]
Basal segment of maxillule articulating with cephalon. [McLaughlin, 1980]

Caridean lobe

External rounded projection on basal part of exopod of 1st maxilliped (Caridea). [McLaughlin, 1980]
External rounded projection on basal part of exopod of first maxilliped (e.g., Caridea). [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) In first maxilliped, setose broadening or lobe at base of outer branch (exopod). [Stachowitsch, 1992]

Caridean shrimps

Higher shrimps, members of the infraorder Caridea; include the majority of shrimps and prawns. [Bliss, 1982]

Caridoid escape reaction

"Tail-flip" behavior resulting from rapid contraction of the ventral abdominal (flexor) muscles, causing the animal to shoot quickly backward from the force of water displaced by the large propulsive surface provided by the tail fan. [Brusca and Brusca, 2002]

Caridoid facies

Aspect of primitive Eumalacostraca distinguished by enclosure of thorax by carapace, movably stalked eyes, biramous antennules, scaphocerite-bearing antennae, thoracopods with natatory exopods, elongate abdomen ventrally flexed and powerfully muscled, and caudal fan. [Moore and McCormick, 1969]
Basic group of characters distinguishing eumalacostracan crustaceans: enclosure of thorax by carapce, movable stalked eye, biramous antennules, antennae with scaphocerites, thoracopods with natatory exopods, ventrally flexed abdomen, and tailfan. [McLaughlin, 1980]

Carina

A raised ridge on the surface of the exoskeleton. [Ingle, 1980]
A ridge or keel of the exoskeleton (Fig. 1, 2).
(pl. carinae) [Perez Farfante and Kensley, 1997]
Any keel-like structure, as on dorsum of pleon on some amphipods; in cirripeds, single compartment plate at end of shell where cirri are protruded, or adjacent to tergum, possessing alae only.
See: Carapace carina [Moore and McCormick, 1969]
Any keellike structure; any well-defined projecting ridge on outer surface of carapace (podocopan Ostracoda); unpaired posterodorsal plate of thoracic Cirripedia (in lepadomorphs 1 of up to 4 unpaired plates of capitulum; in verrucomorphs compartmental plate between rostrum and fixed tergum; in balanomorphs compartmental plate, with alae on each side, opposite rostrum). [McLaughlin, 1980]
Keel, acute ridge, crest. [Poore, 2004]
Keel, or ridge.
(pl. carinae) [Butler, T. H.]
Keel-like ridge or prominence. [Williams, 1984]
Median middorsal ridge on rostrum; oriented parallel to lateral margins of rostrum (see Figs. 37,47). [Hobbs and Jass, 1988]
(Taxon-specific: Order Notostraca) Median keel. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) One of a number of narrow, elevated ridges along carapace or abdomen. According to position and according to group, those on carapace may be termed antennal, branchial, branchiocardiac, gastroorbital, lateral, orbital, posterior, postorbital, postrostral, rostral, subhepatic, submedian, and supraorbital carinae.
(syn. ridge, keel) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) A keel, or acute ridge. [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) A keel, or an acute ridge. [Kensley and Schotte, 1989]
(Taxon-specific: Order Stomatopoda) One in a series of longitudinal, keel-like elevations on dorsal surface of either carapace, thoracic somites (thoracomeres), abdominal somites (pleomeres) or telson. According to position (from midline outward) one may distinguish median, submedian, intermediate, lateral, marginal, and various accessory carinae or secondary ridges. Refers also to ventral elevations (e.g., postanal carina). (sharp, swollen/rounded; posteriorly spined, posteriorly rounded; straight, curved; median carina: bifurcate, not bifurcate). [Stachowitsch, 1992]
Lepas anatifera: left valve removed. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
Balanus trigonus: apical view; left lateral view; and operculum, body, and branchiae. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) One of five primary plates (carina, two scuta, two terga) on outer surface of barnacle: unpaired posterior plate. In stalked form, posterior plate on capitulum. In unstalked barnacle, compartmental plate between rostrum and fixed tergum (asymmetrical form) or plate opposite rostrum (symmetrical form); consists of median paries and lateral alae. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Type of valve sculpture: prominent ridge or keel. (disconnected, excavate, ponticulate = perforate, simple, undercut; dorsal, marginal, median, ventral). [Stachowitsch, 1992]

Carinal

In cirripeds (Thoracica), toward or adjacent to compartment plate termed carina. [Moore and McCormick, 1969]

Carinal latus

See: Latus (carinal) a [Martin, 2005]
See latus. [McLaughlin, 1980]
(Taxon-specific: Subclass Cirripedia) Barnacle shell plate: in stalked form, paired plates (latera), one on each side of carina. Homologous with carinolateral of unstalked form.
(syn. carinolatus) [Stachowitsch, 1992]

Carinal margin

In cirripeds (Thoracica) , edge of tergum adjacent to carina, occluding with carinal margin of opposed tergum. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Edge of any plate adjacent to carina; occluding with carinal margin of opposed tergum (thoracic Cirripedia). [McLaughlin, 1980]

Carinate

Conchostracan valve bearing rib(s), chiefly applicable to Leaiidae. [Moore and McCormick, 1969]
Having a carina, keeled. [Butler, T. H.]
(Taxon-specific: Order Diplostraca) Valve bearing rib(s). [McLaughlin, 1980]
(Taxon-specific: Order Isopoda) Having one or more carinae or acute ridges. [Kensley and Schotte, 1989]

Carinolateral

Compartment plate of cirripeds located on either side of carina, with radii on cardinal side and alae on rostral side.
(syn. latus (cardinal)) [Moore and McCormick, 1969]
Balanus trigonus: apical view; left lateral view; and operculum, body, and branchiae. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) Barnacle shell plate: in unstalked form, paired posterolateral plate, one between carina and each lateral plate. Consists of median paries with radius on one (carinal) side, ala on other (lateral) side.
(syn. carinolatus) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) One of pair of compartmental plates typically overlapping carina on each side, with radius on carinal side and ala on lateral side, sometimes absent; homologous with lepadomorph carinal latus (balanomorph Cirripedia). [McLaughlin, 1980]

Carpocerite

Distal (5th) segment of antennal peduncle. [Moore and McCormick, 1969]
Distal (5th) segment of antennal peduncle. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) In antenna, term applied to last of three segments (ischiocerite, merocerite, carpocerite) of endopod (alternate interpretation: fifth segment of peduncle). [Stachowitsch, 1992]

Carpochelate

(Taxon-specific: Order Isopoda) Having a chela or pincerlike structure formed by the seventh (dactylus) and fifth (carpus) articles of an appendage. [Kensley and Schotte, 1989]

Carpopod

See: Carpus [Martin, 2005]
See carpus [McLaughlin, 1980]

Carpoprodus

(Taxon-specific: Order Mysida) On inner branch (endopod) of thoracopod, multisegmented unit formed by carpus and propodus. [Stachowitsch, 1992]

Carpus

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
Entire animal, right appendages omitted, dorsal view, based on Munida. [Baba, 2005]
(Figure only.) [Baba, 2005]
Endopod of Mxp 3, lateral; and endopod of Mxp 3, including basal 2 articles, distal articles omitted, central. Based on Munidopsis. [Baba, 2005]
(Figure only.) [Baba, 2005]
Antepenultimate segment of thoracopod or pereopod.
(syn. carpopod) [McLaughlin, 1980]
Article 5 of pereopod (article 4 of cheliped). [Holdich and Jones, 1983]
Fifth article of limb (first article of palp in maxilliped 3). [Poore, 2004]
Fifth podomere from the proximal end of a typically 7-segmented appendage (Fig. 3C).
(pl. carpi) [Perez Farfante and Kensley, 1997]
Fifth segment from proximal end of a typically 7-segmented appendage.
(pl. carpi) [Butler, T. H.]
Fifth segment from proximal end of segmented appendage. [Hobbs and Jass, 1988]
Segment of limb located next distally from merus and joined to propodus proximally.
(syn. carpopod(ite), wrist) [Moore and McCormick, 1969]
The fifth segment from the proximal end of a segmented appendage; in some shrimps, consisting of several articles (that of the second pereiopod of alpheids and hippolytids consisting of a number of articles). [Hobbs, Hobbs, and Daniel 1977]
The fifth segment from the proximal end of a typically 7-segmented appendage.
(pl. carpi) [Chace and Hobbs, 1969]
The fifth segment of a thoracic limb.
(syn. carpopodite)
See: Pereopod [Wilson, 1989]
The third podomere from the tip of the endopod of a limb (Figs. 1, 2). [Warner, 1977]
Third article from distal end of leg.
(syn. carpopodite) [Williams, 1984]
Third segment of a pereiopod or maxilliped, counted from the distal end. [Ingle, 1983]
(Taxon-specific: Order Cumacea) Third of five segments (ischium, merus, carpus, propodus, dactylus) of endopod of thoracopod (maxillipeds and pereopods).
(syn. carpopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Fifth of basically seven segments (coxa, basis, ischium, merus, carpus, propodus, dactylus) of thoracopod.
(syn. carpopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Fifth segment of thoracopod; located between merus and propodus. (simple, multiar-ticulated = subdivided).
(syn. carpopod, carpopodite, wrist) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Fifth of basically seven segments (coxa, basis, ischium, merus, carpus, propodus, dactylus) of thoracopod; represents fourth movable (free) segment. In certain amphipods, may form part of subchela (i.e., dactyl and propodus bearing down on carpus).
(syn. carpopodite) [Stachowitsch, 1992]
Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Article 5 or pereopod. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Fifth segment of pereopod; located between merus and propodus.
(syn. carpopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Fourth of basically six segments (preischium, ischium, merus, carpus, propodus dactylus) of inner branch (endopod) of thoracopod, May form a multiarticulate unit with propodus (carpopropodus). (multiarticulate, one-segmented).
(syn. carpopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Fifth segment of thoracic appendage (thoracopod); located between merus and propodus.
(syn. carpopodite) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Fourth of basically six segments (preischium, ischium, merus, carpus, propodus, dactylus) of inner branch (endopod) of thoracopod. Main bend (knee) of thoracopod typically occurs between carpus and propodus.
(syn. carpopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Third of basically five segments (ischium, merus, carpus, propodus, dactylus) of inner branch (endopod) of thoracopod.
(syn. carpopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Fifth segment of thoracopod (third segment of five-segmented endopod); positioned between merus and propodus.
(syn. carpopodite) [Stachowitsch, 1992]

Catalepsis

Bridging of the dorsal surface of the shrimp, as if telson is about to touch rostrum; a defensive position. [Butler, T. H.]

Caudal

Posterior (rear,tail) end of organism. [Hobbs and Jass, 1988]

Caudal appendage

In cirripeds, one of terminal, multiarticulate or uniarticulate, uniramous paired appendages, homologous with caudal furca of other crustaceans. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) One of terminal, multiarticulate or simple, uniramous paired appendages homologous with caudal furca. [McLaughlin, 1980]

Caudal fan

Combination of laterally expanded uropods and telson turned backwards to form powerful swimming structure or means of steering and balancing.
(syn. tail fan, rhipidura) [Moore and McCormick, 1969]
Powerful swimming structure formed of laterally expanded uropods and telson.
(syn. tailfan) [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Tailfan. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Tailfan. [Stachowitsch, 1992]

Caudal filament

See: Caudal ramus [Martin, 2005]

Caudal furca

Pair of caudal rami. [Moore and McCormick, 1969]
Paired caudal rami of terminal abdominal segment or telson.
(syn. furca) [McLaughlin, 1980]
(Taxon-specific: Order Cladocera) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Subapical spine. [Stachowitsch, 1992]

Caudal process

(Taxon-specific: Class Ostracoda) Posterior extension of carapace.
(syn. keel) [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Class Ostracoda) Posterior projection of valve border generally above midheight, or posteroventral, directed upward. [McLaughlin, 1980]
(Taxon-specific: Class Ostracoda) Posterior projection of valve margin. (posterodorsal, posteroventral and upwardly directed). [Stachowitsch, 1992]

Caudal rami

Pair of appendage-like or spine-like processes borne on anal somite in primitive crustaceans. [Brusca and Brusca, 2002]

Caudal ramus

One of paired appendages constituting caudal furca, usually rodlike or bladelike, sometimes filamentous and multiarticular.
(syn. caudal filament, caudal style, cercus, cercopod, furcal ramus, stylet) [McLaughlin, 1980]
Single appendage of terminal abdominal somite paired with another to form caudal furca, both articulated with telson; usually rod-like or blade-like but may be filamentous and multiarticular (caudal filament).
(syn. cercus, cercopod, caudal style, stylet) [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) One of two relatively short, claw-shaped projections at end of postabomen. May bear up to three series (pectens) of minute spines. Both caudal rami together are termed caudal furca. (denticulate, pectinate, with/without basal spine, with/without pectin).
(syn. claw, postabdominal claw, terminal claw) [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) One of two posteriorly directed projections of last segment (telson). Long and segmented ( = annulate, multiarticulate). Both caudal rami together are termed caudal furca. (unarmed, armed with minute spinules and setae).
(syn. furca ramus) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) One of two relatively short, posteriorly directed of projections of telson. Both caudal rami together are termed caudal furca. (claw-like, styliform) (See also uropod).
(syn. cercopod, furcal claw) [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) One of two posteriorly directed projections of last segment (telson). Unsegmented, typically fringed with setae. (freely movable/variously fused with last segment; thin and slender, broadly leaf-like or plate-like).
(syn. furcal ramus, cercopod) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) One of two posteriorly projections of last body segment (telson). Consists of single element with terminal setae (ramal setae, caudal setae). Both rami together are termed caudal furca. If telson is interpreted as representing anal somite, then caudal ramus may be termed uropod. (length relative to telson width: equal to or less than, less than twice, equal to twice). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) One of two posteriorly directed projections of last body segment (telson). Both rami together termed caudal furca. (dorsoventrally flattened and leaf-like, rod-like) (see also uropod).
(syn. furcal ramus) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Pair of minute projections between posterior lobes of abdomen; rami flank anus. (basal, lateral, subbasal, subterminal, terminal).
(syn. anal furca, anal papilla) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) In ascothoracican, one of two posteriorly directed projections of last segment of abdomen. Both caudal rami together termed caudal furca. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) One of two posteriorly directed projections of last abdominal segment (anal somite); typically bears a number of setae (caudal setae). (length greater than, equal to, or less than width; margins: hairy, smooth, spinulose).
(syn. furcal ramus) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The appendage of the posterior abdominal somite of a copepod. It does not have a propodal/ramal configuration and its homologies to serially repeated limbs of the cephalon and thorax have not been determined. The caudal ramus bears setae in a pattern similar to an exopod. Its axial orientation is not known. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) The paired, setiferous and usually articulated structures carried on the anal somite. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Mystacocarida) One of two relatively large, posteriorly directed projections of last segment (telson). Claw-shaped, with serrate inner margin and bearing several major setae. Both rami together are termed caudal furca.
(syn. furcal ramus, furcal claw) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) One of two projections of posterior end (thorax/abdomen) of body; extends anteroventrally due to curvature of body. (paired, unpaired; symmetrical, asymmetrical; lemelliform, rod-shaped, claw-like).
(syn. furcal ramus) [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) One of two unbranched processes projecting posteriorly from anal segment; each ramus bears setae along median margin and terminally. (shorter than, longer than anal segment). [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) In bathynellacean, one of two small protuberances at end of telson. Both caudal rami together termed caudal furca. May also be interpreted as representing lobes of telson.
(syn. furcal ramus) [Stachowitsch, 1992]

Caudal siphon

(Taxon-specific: Class Ostracoda) Posteroventral gape in valve margin; may be extended as tubular structure. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Posteroventral opening in valve border; sometimes produced as tubular structure (Ostracoda). [McLaughlin, 1980]

Caudal style

See: Caudal ramus [Martin, 2005]
See caudal ramus. [McLaughlin, 1980]

Cecum

(Taxon-specific: Order Cladocera) Digestive cecum. [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) One of two outpocketings of midgut. Elongate and extensively branched with carapace. Opens into digestive tract posterior to esophagus/midgut border.
(syn. midgut diverticulum, digestive gland) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Digestive cecum. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Midgut diverticulum. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Hepatic cecum. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Midgut cecum. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Dorsal cecum, lateral cecum. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Digestive gland. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Midgut cecum, rectal cecum. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Highly branched diverticulum, one extending from each side of anterior midgut. Fills greater part of carapace after fish louse feeds on host tissues. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Digestive cecum.
(syn. caecum) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Unpiared anterior extension of stomach. (See also lateral midgut diverticulum).
(syn. midgut cecum, anterior midgut cecum) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Pair of large outpocketings or one of numerous smaller outpocketings of anterior section (stomach) of midgut.
(syn. caecum, liver) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) In anaspidacean, one of numerous relatively thin tubules arising at anterior end of midgut and extending posteriorly to end of thorax. Also refers to short dorsal ceca of midgut, one at level of first abdominal somite, the other level at fifth.
(syn. digestive cecum) [Stachowitsch, 1992]

Celation

(Taxon-specific: Class Ostracoda) Type of valve sculpture: elaboration (tegmen) of outer layer which overlapsand obscures underlying ornamentation. [Stachowitsch, 1992]

Cement gland

Special concentrations of cells in dermal cover of cirripeds which function for secreting calcareous substance of valves; possibly equivalent to dermal glands of other crustaceans. [Moore and McCormick, 1969]
(Taxon-specific: Order Anostraca) Pair of glands dorsal and proximal to eggs in ovisac; produces outer cover of eggs. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Glandular structure, one associated with and opening at base of each antennule. Used by cyprid larva in attachment to substratum.
(syn. adhesive gland) [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Special concentration of cells in dermal cover that secretes calcareous substances of valves (Cirripedia). [McLaughlin, 1980]

Central projection

Terminal projection on crayfish male gonopod formed by fusion of two processes; poorly developed in second form male; located centrally on apex of Procambarus gonopod, distally on that of Cambarus, Fallicambarus, and Orconectes (Figs. 23,32,63). [Hobbs and Jass, 1988]

Cephalasome

Fused five head segments and additional first one or two fused thoracic segments in some copepods. [Brusca and Brusca, 2002]

Cephalic

Pertaining to head; of head. [Hobbs and Jass, 1988]

Cephalic constriction

(Taxon-specific: Subclass Mystacocarida) Constriction delimiting anterior antennulary part of head from posterior part. [McLaughlin, 1980]
(Taxon-specific: Subclass Mystacocarida) Transverse groove dividing head (cephalon) into anterior (antennulary) and posterior parts. [Stachowitsch, 1992]

Cephalic dorsal length

The length of the cephalon measured in a straight line along the dorsal midline from the posterior edge to the anterior vertex or rostrum, depending on which is present. [Wilson, 1989]

Cephalic flexure

Forward or even upward deflection of anterior sterna of some decapods. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) Foward, or sometimes upward, deflection of anterior sterna. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) On underside of cephalothorax, forward, or occasionally upward, deflection of anterior sternum. [Stachowitsch, 1992]

Cephalic hook

(Taxon-specific: Class Cephalocarida) One in a series of minute, anteriorly directed hooks located on underside of head (cephalon); restricted to anterolateral margins. [Stachowitsch, 1992]

Cephalic shield

Chitinous or more or less calcified covering of the head region, formed of fused tergites of cephalic somites, commonly having pleura. [McLaughlin, 1980]
Chitinous, more or less calcified covering structure of head region formed of fused tergites of cephalic somites commonly having pleura. [Moore and McCormick, 1969]
Head shield; the dorsal head tergites fused to form a solid cuticular plate, often with ventrolateral folds ("pleural folds"). [Brusca and Brusca, 2002]
(Taxon-specific: Class Cephalocarida) Broad, semicircular shield covering dorsal surface of head. Formed by fusion of dorsal surfaces (tergites) of first five segments.
(syn. head shield) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Dorsal cuticular shield covering head and thoracic somites (thoracomeres) fused to it. May project anteriorly to form rostrum, posteriorly to form pair of alae. (convex, flat, regionated).
(syn. head shield, dorsal shield) [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Shield-like cuticular structure dorsally convering and folding over front of head (cephalon) and extending somewhat laterally and posteriorly; tapers anteriorly (in one case with narrowest part in middle) and is marked by one or two transverse grooves. (subquadrangular, subrectangular, subtrapezoidal).
(syn. head shield) [Stachowitsch, 1992]

Cephalic somite

One unit of cephalon bearing distnctive pair of appendages.
(syn. cephalomere) [McLaughlin, 1980]
Unit division of head region, generally recognized as one of five such parts which bear distinctive paired appendages (antennules, antennae, mandibles, maxillules, maxillae) in addition to "precephalic" acron bearing eyes. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) Any one of five segments (somites) of head (not including anteriormost acron). According to appendages borne, one may distinguish an antennular, antennal, mandibular, maxillular, and maxillar somite. Fused to each other and to thoracic somites to form cephalothorax.
(syn. cephalomere) [Stachowitsch, 1992]

Cephalomere

Cephalic somite. [Moore and McCormick, 1969]
See cephalic somite. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Cephalic somite. [Stachowitsch, 1992]

Cephalon

A term that refers to the head of a crustacean. [Brusca and Brusca, 2002]
Anterior region of the body bearing the antennules, antennae, eyes, mandibles, maxillules, and maxillae. [Holdich and Jones, 1983]
Anteriormost tagma, bearing eyes, mouth, two pairs of antennae, and three pairs of mouthparts.
(syn. head) [McLaughlin, 1980]
Head, body segments bearing eyes, antennules, antennae, mandibles, maxillules, and maxillae. [Poore, 2004]
Most anterior tagma, bearing eyes, mouth, 2 pairs of antennae, and 3 pairs of mouth-part appendages (e.g., Branchiopoda, Ostracoda, Leptostraca, Bathynella).
(syn. head) [Moore and McCormick, 1969]
The head, or anteriormost body unit. In isopods, the cephalon bears the eyes, mouth, antennulae, antennae, and four pairs of mouthparts (mandibles, maxillulae, maxillae, and maxillipeds). [Wilson, 1989]
(Taxon-specific: Order Cladocera) Head. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Head. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Head. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Anterior of three basic divisions (tagmata) of body (cephalon, thorax, abdomen). Relatively short and covered dorsally by cephalic shield. Consists of five fused segments (somites) bearing antennules, antennae, mandibles, maxillules, and maxillae.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Anterior of three basic divisions (tagmata) of body (cephalon, thorax, abdomen = pleon). Fused with three thoracic somites to form cephalothorax; accordingly, body may be interpreted as being divided into cephalothorax and pleon or into cephalon, pereon and pleon.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Anterior part of cephalothorax. Consists of anterior acron and five cephalic somites and bears eyes, antennules, antennae, labrum, mouth, mandibles, maxillules, maxillae, and labium. First three thoracic appendages (maxillipeds) closely associated with head. Covered, along with thorax, by carapace.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Anterior of three major divisions (tagmata) of body (cephalon, pereon, pleon). Typically laterally compressed and fused with first (occasionally also second) thoracic somite to form cephalothorax. The term head is often used synonymously with cephalothorax. (with/without rostrum, anteriorly truncate; laterally compressed, dorsoventrally flattened).
(syn. head)
See: Lateral lobe, Postantennal sinus [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Anterior division (tagma) of body bearing eyes, mouth, two antennules, two antennae, and three pairs of mouthparts; fused with first thoracic segment, in certain cases also with second, and therefore occasionally referred to as a cephalothorax.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Anterior region of body or head; more correctly the cephalothorax in isopods, as the first pereonal segment is usually fused with the head. [Kensley and Schotte, 1989]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Head; strictly speaking the cephalon of an isopod is a cephalothorax, as it is always fused with the first thoracomere (and also with the second thoracomere in the Gnathiidea). [Wetzer et al. 1997]
(Taxon-specific: Order Stomatopoda) Anterior division (tagma) of body (cephalon, thorax, abdomen). Consists of an anterior acron and five somites and bears eyes, antennules, antennae, epistome, labrum, mouth, mandibles, maxillules, and maxillae. Covered, along with first four somites (thoracomeres) of thorax, by carapace.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Anterior of three divisions (tagmata) of body (cephalon, thorax, abdomen). Consists of five somites bearing antennules, antennae, mandibles, maxillules, and maxillae. Covered by rostral plate and, posteriorly, by carapace.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Anterior part of cephalothorax (or anterior of three tagmata of body: cephalon, pereon, abdomen). Partially fused to first thoracic somite and delimited from last three thoracic somites (pereon) by cervical groove and ridges on carapace. Bears antennules, antennae, preoral sting, proboscis with mandibles, mouth and modified lips, maxillules and maxillae.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) A complex of all of the somites of the head. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) Anterior of three basic divisions of body (cephalon, thorax, abdomen). Consists of five (cephalic) somites and bears antennules, antennae, labrum, mouth, labium, mandibles, maxillules, and maxillae. Fused with one or more thoracic somites (thoracomeres) to form cephalosome.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Head: the anterior region of the body, comprising the first five somites (antennulary to maxillary somites). [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Mystacocarida) Anterior of three basic division of body (according to interpretation, either cephalon, maxillipedal somite, thoracoabdomen, or cephalon, thorax, abomen). Relatively large and divided into anterior (antennulary) and posterior parts by groove (cephalic constriction). Bears antennules, antennae, mandibles, maxillules, and maxillae.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Head. [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Anterior division of body (cephalon, trunk) bearing frontal processes, antennules, anteannae, labrum, mouth, mandible, maxillules, maxillae, and maxillipeds; covered dorsally by cephalic shield. First trunk segment fused to cephalon.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Head. [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Anterior of three basic divisions (tagmata) of body (cephalon, thorax, abdomen). Fused with first thoracic somite, leading to alternate interpretation (cephalon, pereon, abdomen). Covered by carapace. (See also cephalothorax).
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Anterior part of cephalothorax. Consists of five cephalic somites bearing antennules, antennae, mandibles, maxillules, and maxillae. Covered, along with thorax, by carapace.
(syn. head)
See: Protocephalon [Stachowitsch, 1992]

Cephalosome

Head region when this includes only somites bearing maxillipeds or gnathopods, or both. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Copepoda) Head region with one or two fused thoracic somites (Copepoda). [McLaughlin, 1980]
(Taxon-specific: Subclass Copepoda) One of three divisions (tagmata) of body (cephalosome, metasome, urosome); consists of head and one or two thoracic somites (thoracomeres) fused to it. Cephalosome and metasome together from prosome. (See also cephalothorax). [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The anterior tagma of the body in copepods, covered by the dorsal cephalic shield and comprising 5 cephalic somites and the first thoracic (maxilliped-bearing) somite. [Boxshall and Halsey, 2004]

Cephalothoracic ganglion

(Taxon-specific: Order Decapoda) In crab-like (brachyuran) decapod, large concentration of nerve tissue posterior to esophagus. Consists of fused ganglia of thoracic somites (thoracomeres).
(syn. postesophageal ganglion) [Stachowitsch, 1992]

Cephalothorax

A fused dorsal covering resulting when the carapace extends dorsally and laterally and/or posteriorly and fuses dorsally with one or more thoracic segments. [Brusca and Brusca, 2002]
All fused somites of the cephalon (head) and thorax, covered in Decapoda by carapace. [Poore, 2004]
Anterior part of body composed of fused cephalic and thoracic somites; latter with appendages modified as mouthparts, sometimes also with relatively unmodified appendages. [McLaughlin, 1980]
Anterior part of body composed of united cephalic and thoracic somites, latter comprising not only those with appendages modified as mouth parts or for food capture but others with relatively unmodified appendages, all forming a fused complex. [Moore and McCormick, 1969]
Anterior part of the body consisting of the fused cephalon (head) and thorax, bearing all the apendages except the pleopods and uropods. [Perez Farfante and Kensley, 1997]
Cephalon and first two thoracomeres. [Holdich and Jones, 1983]
Fused anterior part of the body bearing all body appendages except pleopods and uropods. [Butler, T. H.]
Portion of body bearing eyes and all appendages through fifth pereiopod (fused head and thorax). [Hobbs and Jass, 1988]
Region of the body in decapod crustaceans that is covered by the carapace, with the boundary between head and thorax indicated by the cervical groove. In lobsters the cephalothorax is called the "body;" in shrimps it is called "head.". [Bliss, 1982]
The body of a crab; formed from the fusion of the head and thorax, enclosed dorsally and laterally by the carapace and ventrally by the sternum. [Warner, 1977]
The fused anterior part of the body bearing all of the appendages except the pleopods and uropods. [Chace and Hobbs, 1969]
The fused head and thorax, enclosed dorsally and laterally by the carapace and ventrally by the sternum. [Ingle, 1983]
The fused head and thorax. [Ingle, 1980]
The portion of the body bearing the eyes and all of the appendages through the fifth pereiopod. [Hobbs, Hobbs, and Daniel 1977]
(Taxon-specific: Order Cumacea) Expanded anterior section of body consisting of head (cephalon) fused with first three thoracic somites. Covered by and fused dorsally and laterally with carapace. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Term applied to anterior section of body consisting of head and first two thoracic segments (thoracomeres); covered dorsally by carapace. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Anterior division (tagma) of body (cephalothorax, abdomen). Consists of head (cephalon) fused with thorax and is largely or entirely covered by carapace. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Term applied to anterior section of body consisting of head (cephalon) fused with first (and occasionally with second) thoracic somite.
(syn. head) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Term applied to anterior section of body consisting of head (cephalon) fused with first (and occasionally second) thoracic segment. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Anterior section of body consisting of head and, according to interpretation, either those anterior thoracomeres fused to head or entire thorax. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Anterior division (tagma) of body (cephalothorax, abdomen). Consists of head (cephalon)-fused with thoracic somite-and remaining three thoracomeres; anterior position covered by carapace. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) A complex of the cephalic somites plus at least one thoracic somite. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) Anterior region of body including head (cephalon) and thoracic somites (thoracomeres) fused to it. Cephalosome and metasome together form prosome. (See also cephalothorax). [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The anterior tagma of the body in copepods in which the first pedigerous somite (=second thoracic) is incorporated into the cephalosome and covered by an extended dorsal shield. [Boxshall and Halsey, 2004]
(Taxon-specific: Class Ostracoda) Term occasionally applied to major part of body comprising fused head (cephalon) and thorax. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Term occasionally applied to part of body consisting of head and fused first thoracomere. [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Term applied to anterior section of body consisting of cephalon and first thoracic somite (thoracomere). This unit may also be expressed by term cephalon. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Anterior division (tagma) of body (cephalothorax, abdomen). Consists of head (cephalon) fused with thorax. Covered dorsally (incompletely on sides) by carapace. [Stachowitsch, 1992]

Cercopod

See: Caudal ramus [Martin, 2005]
See caudal ramus [McLaughlin, 1980]
(Taxon-specific: Order Notostraca) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Caudal ramus. [Stachowitsch, 1992]

Cercus

See: Caudal ramus [Martin, 2005]
See caudal ramus
(pl. cerci) [McLaughlin, 1980]

Cerebral ganglion

(Taxon-specific: Subclass Cirripedia) Supraesophageal ganglion. [Stachowitsch, 1992]

Cervical carina

Mesially transverse and laterally oblique ridge extending from the anterior limit of the hepatic region towards middorsal line of carapace (Fig. 2A). [Perez Farfante and Kensley, 1997]

Cervical furrow

See: Cervical groove [Martin, 2005]
(Taxon-specific: Order Decapoda) See: Carapace grooves d [McLaughlin, 1980]

Cervical groove

See: Carapace groove c [Martin, 2005]
A groove or series of grooves sometimes present on the carapace; it is mesially transverse, laterally oblique, and separates the gatric and hepatic regions from the cardiac and branchial regions. [Chace and Hobbs, 1969]
Groove across the middle of the carapace between gastric and cardiac regions, curving forwards laterally, sometimes incomplete medially, sometimes accompanied by cervical ridge and ending laterally in cervical incision in some lobsters, sometimes with paired postcervical spines. [Poore, 2004]
Major arclike suture (groove) on carapace of crayfish, dividing it into anterior (cephalic) and posterior (thoracic) regions (see Fig. 14). [Hobbs and Jass, 1988]
The complex groove running along the dorsal surface of the carapace, being transverse in the middle and turning obliquely forward on each side to the lateral margins. [Ingle, 1983]
The major arc-like suture on the carapace of a crayfish, dividing it into cephalic and thoracic regions. [Hobbs, Hobbs, and Daniel 1977]
(Taxon-specific: Order Notostraca) Somewhat curved, transverse groove in anterior third of carapace; corresponds to border of head and thorax. (See also mandibular groove). [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) transverse groove across dorsal surface of head; corresponds to level of mandibles. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) See: Carapace grooves, Stomatopod integumental ornamentation [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) On carapace, well-defined, transverse groove separating gastric and cardiac regions. Considered to represent former border between two cephalic somites.
(syn. cervical suture, cervical furrow) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Transverse groove across posterior third of carapace. (See also gastric groove). [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) In carapace, transverse groove delimiting cephalon (including first thoracic somite) from remaining three thoracic somites (pereon).
(syn. transverse groove) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) In anaspidacean, transverse groove across head.
(syn. mandibular groove, mandibular sulcus) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Transverse groove across anterior region of carapace. [Stachowitsch, 1992]

Cervical notch

Strong indentation of carapace at level of cervical groove (e.g., scyllarid palinurans).
(syn. cervical incision) [Moore and McCormick, 1969]
Strong indentation of carapace at level of cervical groove. [McLaughlin, 1980]
(Taxon-specific: Order Cladocera) Transverse groove between head and trunk (with/without conspicuous folds).
(syn. cervical sinus) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) On dorsal surface of carapace, strong indentation at level of cervical groove.
(syn. cervical incision) [Stachowitsch, 1992]

Cervical sinus

Rounded to angular indentation at front of cladoceran carapace along dorsal edge, exposing rear part of head. [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) Cervical notch. [Stachowitsch, 1992]
(Taxon-specific: Order Cladocera) Rounded to angular indentation anteriorly along dorsal edge of carapace (Cladocera). [McLaughlin, 1980]

Cervical spine

Spine on lateral surface of carapace immediately posterior to cervical groove of crayfishes (see Fig. 14). [Hobbs and Jass, 1988]
Spine on the lateral surface of the carapace immediately posterior to the cervical groove in crayfishes. [Hobbs, Hobbs, and Daniel 1977]

Cervical sulcus

Groove or series of grooves sometimes present on carapace; mesially transverse, laterally oblique, and separates gastric and hepatic regions from cardiac and branchial regions.
(syn. (or groove)) [Butler, T. H.]
Mesially transverse and laterally oblique groove of the carapace extending from the anterior limit of the hepatic region towards the midline of the carapace (Fig. 2B). [Perez Farfante and Kensley, 1997]
(Taxon-specific: Order Mysida) Transverse groove across anterior region of carapace at level of mandibles.
(syn. cervical groove) [Stachowitsch, 1992]

Cervical suture

See: Cervical groove [Martin, 2005]
See cervical groove. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Cervical groove. [Stachowitsch, 1992]

Chaetotaxy

The form, number, and shapes of the setae. [Wilson, 1989]

Chalimus

(Taxon-specific: Subclass Copepoda) One of up to four stages in copepodid phase of development of caligid-like parasitic copepods; the chalimus usually is attached to the host, often by a frontal filament held by maxilla 2. The first chalimus is molted from the first copepodid stage; the four chalimus stages correspond to the second to fifth copepodid stages. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) The post-copepodid developmental stage of most siphonostomatoid fish parasites, characterised by possession of a frontal filament for attachment to the host. [Boxshall and Halsey, 2004]

Chela

A claw formed by the dactyl and propodus or a limb. Incorrectly used in euphausiids to describe setae in the configuration of a claw. [Mauchline, 1984]
A claw, or the claw-like terminus of a cheliped. [Bliss, 1982]
A forceps-like structure consisting of the two distal-most podomeres of a pereiopod. [Hobbs, Hobbs, and Daniel 1977]
A pincer formed by the two distal podomeres of a pereiopod in which the movable finger or dactyl opposes a fixed finger formed by a distal extension of the propodus.
(pl. chelae) [Chace and Hobbs, 1969]
A pinching claw composed of a moveable finger, the dactylus, and a fixed finger, a distal extension of the propodus (Fig. 1). If a pair of chelae differ in size the larger is called the major chela and the smaller the minor. [Warner, 1977]
Appendage ending in chela (claw).
(pl. chelae) [Perez Farfante and Kensley, 1997]
Arrangement of distal 2 articles of crustacean limb in which terminal article is opposed to article preceding it in an adaptation for grasping. In true chela, terminal 2 articles shaped as fingers, one closing against other. In subchela, terminal article (dactyl) usually closes against distal surface of penultimate article (propodus). [Williams, 1984]
Claw formed by the two distal segments of a periopod, in which the movable finger or dactylus opposes a fixed finger formed by the distal extension of propodus.
(pl. chelae) [Butler, T. H.]
Claw or pincer, derived from interacting fixed finger (extension from palm of propodus) and moveable finger (dactylus); palm refers. [Poore, 2004]
Distal part of appendage; pincerlike, with opposable movable and immovable fingers; occasionally both fingers moveable.
(pl. chelae) [McLaughlin, 1980]
Forcepslike structure ("claw" or "pincer"), consisting of two opposed distal podomeres of first, second and third pereiopods of crayfishes, first and second pereiopods of shrimps; dactyl (moveable finger) and propodus (see Figs. 13,14). [Hobbs and Jass, 1988]
Pincer-like distal part of limb consisting of opposed moveable, and immovable fingers. [Moore and McCormick, 1969]
The two distal segments of a cheliped forming a pinching claw. [Ingle, 1983]
(Taxon-specific: Order Tanaidacea) Pincer-like structure at end of cheliped (first pereopod). Formed by movable finger (dactylus) opposed by immovable distal extension of propodus. Highly variable according to sex and stage of maturity.
See: Subchela [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Pincer-like structure at end of appendage. Formed by movable finger (dactylus) opposed by immovable distal extension (fixed finger) of expanded propodus (manus). (heterochelous, crushing, tearing).
(syn. pincer, claw)
See: Subchela [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Pincer-like structure of first two pereopod pairs (gnathopods). Formed by movable finger (dactylus) opposed by immovable distal extension of propodus.
See: Subchela [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Distal pincerlike part of appendage, often formed by a mobile and an immobile finger. [Kensley and Schotte, 1989]
(Taxon-specific: Class Ostracoda) In maxilla of certain male, hook-like structure formed by segments of inner branch (endopod); used to hold female during copulation. May also refer to pincer-like structure formed by middle segment of endopod in second (last) pair of thoracopods; used to clean food from maxillule.
(syn. pincer) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Pincer-like structure at end of third thoracopod in certain euphausiaceans. Formed by movable dactylus bearing down on rigid spine(s) projecting distally from propodus. [Stachowitsch, 1992]

Chelate

An appendage in which the movable dactylus is apposed to an equally well-developed distal prolongation of the propodus. [Ingle, 1980]
Bearing a chela. [Butler, T. H.]
Bearing chela (chelae). [Moore and McCormick, 1969]
Pincer-like condition in which dactylus closes against fixed forward projection of propodus. [Holdich and Jones, 1983]
Pincerlike. [McLaughlin, 1980]
The dactyl and distal part of the propodus of a pereiopod forming a pinching claw. [Ingle, 1992]
(Taxon-specific: Order Isopoda) Having a chela; modified to form a pincer. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Having a chela; the propodus and dactylus forming a pincerlike structure wherein the latter articulates submedially on the former to produce a "moveable and fixed finger" arrangement. (True chelae are extremely rare in isopods.). [Wetzer et al. 1997]

Cheliped

A pereiopod bearing a chela. [Chace and Hobbs, 1969]
A pereiopod bearing a chela; in crayfishes, the first pereiopod. [Hobbs, Hobbs, and Daniel 1977]
Any thoracopod bearing chela. [McLaughlin, 1980]
Pereiopod bearing chela (see Figs. 13,14), in crafish literature applied almost exclusively to first pereiopod. [Hobbs and Jass, 1988]
(Taxon-specific: Order Tanaidacea) Modified second thoracopod (= first pereopod). Typically consists of only five segments (basis, merus, carpus, propodus, dactylus), with coxa and ischium being absent. (chelate, subchelate; symmetrical, asymmetrical).
(syn. chelipede) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Any chela-bearing thoracopod; typically refers to first pair(s) of pereopods. (equal, unequal: major, minor). [Stachowitsch, 1992]

Chelipeds

A limb bearing a chela. In crabs this limb is borne on the fourth thoracic segment (Fig. 1). [Warner, 1977]
Any thoracopod bearing chelae. [Moore and McCormick, 1969]
One or more pairs of thoracic legs of decapod crustaceans that terminate in a chela, or claw. Often the entire cheliped is referred to as a claw. [Bliss, 1982]
Pair or pairs of thoracic legs behind maxillipeds; bearing chelae, or pincer-like claws, and often stouter, sometimes much stouter, than other legs. [Williams, 1984]
Pereiopod bearing a chela. [Butler, T. H.]
Second pair of thoracic appendages; chelate in form. [Holdich and Jones, 1983]
The first pair of pereiopods arising opposite the first (or fourth) sternite and bearing the chelae. [Ingle, 1983]

Chirocerate

(Taxon-specific: Subclass Copepoda) Used of male antennules with one very swollen, thick walled segment and with only one segment distal to the geniculation. [Boxshall and Halsey, 2004]

Chitin

A resistant complex chemical compound, the chief constituent of the exoskeleton, or shell, of crustaceans. [Bliss, 1982]
Constituent of the shell or integument of a shrimp. [Butler, T. H.]

Chromatophore

A cell (simple or branched), usually in shell (cuticular or subcuticular), containing pigment granules, usually capable of being dispersed or concentrated. [Butler, T. H.]
Cell containing pigment. [Holdich and Jones, 1983]
Cells whose cytoplasm contains pigment that can be rapidly concentrated or dispersed, producing an overall effect of altering the color or tone of the whole or part of the animal. [Ingle, 1983]
Pigmented cell in exoskeleton. [Poore, 2004]
(Taxon-specific: Order Decapoda) Pigment-filled, sac-shaped cell; contraction and expansion of chromatophores result in color changes. (bichromatic = dichromatic, monochromatic, polychromatic). [Stachowitsch, 1992]

Cicatrix

Longitudinally disposed ridge(s) often present on lateral part of sixth abdominal somite (Fig. 1).
(pl. cicatrices) [Perez Farfante and Kensley, 1997]

Cincinnuli

Minute hooked processes interlocking halves of petasma (Dendrobranchiata). [Poore, 2004]
Minute interlocking processes projecting from the dorsomesial margins of the petasmal endopods (Fig. 4B).
(pl. cincinnulus) [Perez Farfante and Kensley, 1997]

Cincinnulus

See: Retinaculum [Moore and McCormick, 1969]
See retinaculum. [McLaughlin, 1980]

Circumboreal

Pertaining to geographical distribution that encompasses all marine areas in colder parts of the northern hemisphere. [Butler, T. H.]

Circumesophageal connective

(Taxon-specific: Order Decapoda) One of two strands of nerve tissue surrounding esophagus and connecting dorsal supraesophageal ganglia with posterior subesophageal ganglia. May bear ganglia (paraesophageal ganglia).
(syn. esophageal connective) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) One of two short, relatively thick strands of nerve tissue surrounding esophagus and connecting dorsal supraesophageal ganglion with subesophageal ganglion. Innervates antennae.
(syn. paraesophageal connective) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) One of two strands of nerve tissue surrounding esophagus and connecting supraesophageal ganglion to ventral nerve cord.
(syn. esophageal connective) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) One of two strands of nerve tissue surrounding esophagus and forming lateral part of circumesophageal nerve ring. Joins supraesophageal ganglion and complex formed by subesophageal ganglion and more or less concentrated ventral nerve cord. [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) One of two strands of nerve tissue surrounding foregut and joining dorsal brain to ventral nerve cords. [Stachowitsch, 1992]

Circumesophageal ganglion

(Taxon-specific: Order Diplostraca) Brain. [Stachowitsch, 1992]

Circumesophageal nerve ring

(Taxon-specific: Class Ostracoda) Well-developed ring of nerve tissue surrounding esophagus; consists anteriorly of supraesophageal ganglion, laterally of circumesophageal connective, and posteriorly of complex formed by subesophageal ganglion and more or less concentrated central nerve cord. [Stachowitsch, 1992]

Circumgenital body cavity

(Taxon-specific: Subclass Branchiura) Genocoel. [Stachowitsch, 1992]

Circumgnathal

Around the biting or grinding surface, as in circumgnathal denticles. [Wilson, 1989]

Circumoral connective

(Taxon-specific: Order Stomatopoda) One of two long strands of nerve tissue surrounding anterior section of digestive tract and joining supraesophageal ganglion to postoral ganglion.
(syn. esophageal connective) [Stachowitsch, 1992]

Cirral fan

Lepas anatifera: cirrus V; cirrus I, and extended cirral fan. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
Balanus trigonus: cirri V, III, II, and I, and extended cirral fan. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]

Cirri

Feathery thoracopods used for suspension feeding in many barnacle groups. [Brusca and Brusca, 2002]
Long, feathery biramous thoracopods of sessile thoracican barnacles. [Brusca and Brusca, 2002]
Lepas anatifera: left valve removed. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
Lepas anatifera: rostral view; and left valve and cirri removed. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
Balanus trigonus: cirri V, III, II, and I, and extended cirral fan. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]

Cirrus

Multiarticulate food-gathering appendage of "thoracic" region of cirriped, normally one of six pairs, each with two long hairy rami curled towards mouth. [Moore and McCormick, 1969]
Penes; specialized reproductive organ of pentastomids; the term penes can also refer to reproductive appendages or structures in other taxa. [Brusca and Brusca, 2002]
Lepas anatifera: cirrus V; cirrus I, and extended cirral fan. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) One of up to six pairs of elongate appendages of thorax regions (those of ascothoracican being termed thoracopods). Biramous, basically consisting of proximal protopod and distal endopod and exopod. Reduced and set-off pair of cirri in acrothoracican are termed mouth cirri. (uniramous, biramous; acanthopodus, ctenopodous, lasiopdous). [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Thoracic, usually biramous, multiarticulate appendage generally flattened laterally and curled anteriorly, with food-gathering function; anterior and posterior margins designated lesser and greater curvature respectively.
(pl. cirri) [McLaughlin, 1980]

Clasper

Appendage, including antenna, modified for holding female during copulation; or an organ for fixation in parasites. [McLaughlin, 1980]
Appendage, including antenna, that serves for attachment in copulation or as organ for fixation in parasites. [Moore and McCormick, 1969]
(Taxon-specific: Order Diplostraca) Modified first and occasionally also second pair of trunk appendages in male; distal endites elongated and hook-like. Serves in grasping female during copulation. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Term applied to well-developed antennae in male; used to clasp famale during copulation. [Stachowitsch, 1992]

Class

A major subdivision of a phylum in the classification of animals, usually consisting of several subclasses and orders. [Bliss, 1982]

Clava

(Taxon-specific: Class Ostracoda) Type of valve sculpture: tubercle-like projection elongated in longitudinal direction or parallel to margin. If arranged in a series, clavae may represent disconnected ridge (carina). (cruciform). [Stachowitsch, 1992]

Clavate

(Taxon-specific: Order Isopoda) Club shaped; having one end thickened. [Kensley and Schotte, 1989]

Clavus

(Taxon-specific: Subclass Copepoda) An accessory spiny process on the apex of basis of the maxilla of some siphonostomatoids. [Boxshall and Halsey, 2004]

Claw

a modified seta found on the distal segment of the walking legs that is heavily sclerotized and has a sharp tip. [Wilson, 1989]
(Taxon-specific: Order Cladocera) Caudal ramus. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) One of up to several claw-like projections from last segment of inner branch (endopod) of maxillae or thoracopods. Inner border may bear series of fine denticles. Largest claw occasionally termed "dactyl."
(syn. endopodal claw) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Chela. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Any claw-shaped projection of limb or caudal ramus. (subterminal, terminal; smooth, toothed) (See also chela). [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Claw-like tip of last segment of maxillules, maxillae, and maxillipeds. one may distinguish the talon of the maxillules, which has a pore for the maxillulary glands, and the claws of the maxillae and maxillipeds, which usually have secretory? or sensory? pores. (arcuate, horseshoe-shaped, talon-like, trifid, 10-pronged).
(syn. fang) [Stachowitsch, 1992]

Cleaning setae

Unusual setulate setae used to clean the antennae or antennulae. These setae are located on the distal segment of the mandibular palp. [Wilson, 1989]

Closed petasma

The lateral lobes are heavily sclerotized, sometimes making structure virtually rigid, with the ventral costae situated ventromesially, almost abutting, and delimiting a small, sometimes extremelyso, space; lateral lobe usually produced distally into lateral sprouts or horns.
See: Petasma [Perez Farfante and Kensley, 1997]

Closed thelycum

One in which the seminal vesicles are present.
See: Thelycum [Perez Farfante and Kensley, 1997]

Closer muscle

The muscle which moves the dactlyus downwards relative to the propodus (Fig. 12, 13). [Warner, 1977]

Clypeus

An unpaired dorsal unit of the cephalon bearing the labrum medially and the mandibular fossae laterally. The fossae articulate with the dorsal condyle of the mandibles. [Wilson, 1989]
Part of head carrying labrum; plate on anterior medial part of head formed by fusion of basal segments of antennae (e.g., Branchipus, also Hexapoda). [Moore and McCormick, 1969]
(Taxon-specific: Order Anostraca) Part of cephalon carrying labrum; plate anteromedially on head formed by fusion of basal segments of antennae. [McLaughlin, 1980]
(Taxon-specific: Order Anostraca) Plate-like structure fromed by medial fusion of bases of antennae. (with/without digiform process).
(syn. frontal plate) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) On underside of head, plate-like structure bearing upper lip (labrum). Separated from labrum by suture. [Stachowitsch, 1992]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) In most (but not all) isopods the labrum consists of two pieces; the anteriormost (proximal) piece is referred to as the clypeus, the posteriormost (distal) piece as the labrum proper. [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Part of head (cephalon) bearing upper lip (labrum). [Stachowitsch, 1992]
Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Platelike structure of cephalon, anterior to upper lip or labrum, sometimes fused with frontal lamina. [Kensley and Schotte, 1989]

Colleteric gland

In Cirripedia (Rhizocephala), a single or paired sac-like gland in female or hermaphrodite, producing viscid material binding eggs together. [Moore and McCormick, 1969]
(Taxon-specific: Suborder Rhizocephala) Single or paired gland in female or hermaphrodite producing viscid material for binding eggs together. [McLaughlin, 1980]

Comb

(Taxon-specific: Class Cephalocarida) Ventral comb. [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Telsonic comb. [Stachowitsch, 1992]

Comb collar

In Cirripedia (Acrothoracica), retractable membranous collar supporting row of numerous uniform setae at superior angle of aperture. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) In acrothoracican, collar-like structure surrounding upper part of aperture. Retractable, consisting of membranous fold with fringe of setae. [Stachowitsch, 1992]
(Taxon-specific: Superorder Acrothoracica) Retractable membrane supporting row of uniform setae, at superior angle of aperture. [McLaughlin, 1980]

Combinatorial stages

Larvae exhibiting a combination of characters from the preceding and succeeding stages so that the resulting stage appears generally more (or less) advanced than the normal numeric stage. [Ingle, 1992]

Commensal

An association in which food is shared or taken by one partner from the other without greatly harming it. [Ingle, 1983]

Compartment plate

In sessile cirripeds (Verrucomorpha, Balanomorpha), rigid articulate skeletal element (valve) forming part of shell wall.
(syn. mural plate) [Moore and McCormick, 1969]
One of several rigidly articulated plates forming wall in sessile cirripeds. [McLaughlin, 1980]
(Taxon-specific: Subclass Cirripedia) In unstalked barnacle, one of up to eight overlapping/articulating plates forming wall which encircles body. May include form anterior to posterior end: single rostrum, paired rostrolaterals, laterals, carinolaterals, single carina, and in asymmetrical form, also fixed scutum and fixed tergum.
(syn. compartmental plate, mural plate) [Stachowitsch, 1992]

Complemental plate

(Taxon-specific: Subclass Cirripedia) In barnacle, term applied to relatively small male attached to hermaphroditic individual. (See also dwarf male). [Stachowitsch, 1992]

Complex

(Taxon-specific: Subclass Copepoda) Two or more unarticulated somites or segments resulting from the failure of an arthrodial membrane to form between the somites or segments comprising the complex. [Ferrari and Dahms, in press]

Compound eye

Array of contiguous ommatidia having common optic nerve trunk; paired. [Moore and McCormick, 1969]
Paired array of contiguous ommatidia having common optic nerve trunks. [McLaughlin, 1980]
(Taxon-specific: Order Cladocera) One of two large photosensitive organs on head; sessile, typically fused, and enclosed within optic vesicle. Movable by series of optic muscles. Relative position of compound eye on head (e.g., anterior, in middle near ventral margin) may be of taxonomic importance. [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) One of two larger photosensitive organs located on sloping anterior part of carapace; sessile. (See also eye tubercle, nauplius eye).
(syn. lateral eye) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) One of two large photosensitive organs located on anterior end of head; sessile, either closely adjoining or partially fused. Enclosed almost entirely within optic vesicle. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) One of two relativel large, stalked photosensitive organs projecting from each side of head. (See also nauplius eye). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Eye. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) One of two organs of vision suspended in a blood sinus on dorsal surface of carapace; each movable eye consists of numerous ommatidia, yet lacks true outer cornea. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Cypris larva. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) One of two more complex anterodorsal organs of vision. Each is contained in ocular sinus beneath eye tubercle. (See also nauplius eye). [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Pair of larger organs of vision, each located distally on eyestalk (ocular peduncle), (divided = bilobed = multilobed, undivided = single-lobed = spherical, imperfect). [Stachowitsch, 1992]

Compound rostrum

In cirripeds (Balanomorpha), projection formed by fusion of rostrolateral plates, forming compound compartment overlapping latera, and on which radii may develop (cf. rostrum). [Moore and McCormick, 1969]
Balanus trigonus: apical view; left lateral view; and operculum, body, and branchiae. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
Balanus trigonus: wall plates, exploded; and interior of operculum. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) Compartmental plate formed by fusion of rostrolaterals with rostrum or of rostrolaterals, with rostrum missing (balanomorph Cirripedia). [McLaughlin, 1980]
(Taxon-specific: Subclass Cirripedia) Rostrum. [Stachowitsch, 1992]

Compressed

Flattened from side to side, or laterally. [Butler, T. H.]

Conchostracan carapace interspace

Area between any 2 growth lines of conchostracan carapace.
(syn. used interchangeably include intervales, growth zone, growth band) [Moore and McCormick, 1969]

Conchostracan carapace interval

Space between any 2 ribs, costae, or costellae on conchostracan carapace. [Moore and McCormick, 1969]

Conchostracan carapace ribs

Strong radial ridges radiating from and across umbo of conchostracan carapace, with intervals of variable width between any pair and commonly nodose at intersections of growth lines; may be partial or embryonic in expression; synonyms include longitudal striae, carinae, radials, diagonal ridges, radial costae, and keels. [Characterize Leaiidae, never exceeding five in number on any given leaian valve; ribs also occur in Protomonocarina and Limnadiopsileaia.]. [Moore and McCormick, 1969]

Condyle

A heavily sclerotized projection of the mandible's dorsal surface that articulates with the cephalon in the clypeal fossa. [Wilson, 1989]
Knob; rounded process at base of central projection of male first pleopod (gonopod); "condyl length" as presented in Tables 4,6,8,10 is measured distance between base of condyl and distal tip of central projection (Fig. 32). [Hobbs and Jass, 1988]

Conglobate

(Taxon-specific: Order Isopoda) Able to roll up into a ball, as in some sphaeromatid and oniscidean isopods. [Kensley and Schotte, 1989]

Conspecific

(Taxon-specific: Order Isopoda) Belonging to the same species. [Kensley and Schotte, 1989]

Contiguous

(Taxon-specific: Order Isopoda) Touching. [Kensley and Schotte, 1989]

Conulus

(Taxon-specific: Class Ostracoda) Type of valve sculpture: conical spine. [Stachowitsch, 1992]

Copepodid

Postnaupliar developmental stages of copepods. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Copepoda) A developmental stage without a naupliar arthrite on antenna 2, usually with articulating thoracic somites and more than three transformed limbs, and often with articulating abdominal somites. Copepodid stages are designated by Roman numerals. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) Postnaupliar developmental stage (Copepoda). [McLaughlin, 1980]
(Taxon-specific: Subclass Copepoda) The postnaupliar phase in copepod development. [Boxshall and Halsey, 2004]

Copepodite

Postnaupliar stage (= a small juvenile) recognized in some copepod groups. [Brusca and Brusca, 2002]

Copulation

Joining of male and female for transference of spem; sexual union. [Hobbs and Jass, 1988]

Copulatory limbs

(Taxon-specific: Class Ostracoda) Male limbs modified for copulation, at least in most Myodocopa, usually the 8th limb pair.
See: Hemipenes [Cohen, Peterson, and Maddocks, in press]

Copulatory male

A fully adult male. In the janiroidea isopods, the male is identified by a sperm tube on the second pleopod's stylet, which is open at its sharp distal tip. In some specimens at this terminal stage, the vas deferens is visible through the cuticle connecting to the penile papilla. [Wilson, 1989]

Copulatory organ

Third pair of trunk limbs, bearing the gonopores, in ostracodes. [Brusca and Brusca, 2002]

Copulatory pore

(Taxon-specific: Subclass Copepoda) In female reprductive system, pore on ventral surface (sternite) of first abdominal segment (genital somite). Opens into seminal receptacle and thus represents, along with two gonopores, third opening of reproductive system. [Stachowitsch, 1992]

Copulatory stylet

(Taxon-specific: Order Isopoda) Structure situated on endopod of pleopod 2 in males, used for transfer of spermatophore in some species; also referred to as appendix masculina. [Kensley and Schotte, 1989]

Cor frontale

Anterior accessory circulatory pump that helps maintain blood pressure in large or active crustaceans. [Brusca and Brusca, 2002]
Special pulsating structure or accessory heart formed from enlargement of blood vessel; contraction caused by outer tangential muscles or internal muscles derived from muscles having other functions. [McLaughlin, 1980]
(Taxon-specific: Order Cumacea) In circulatory system, small, muscular expansion of anterior aorta. Located in head; supports heart in pumping blood anteriorly.
(syn. cephalic heart) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) In circulatory system, small muscular expansion of anterior aorta. Located in head; supports heart in pumping blood anteriorly.
(syn. cephalic heart) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) In circulatory system, muscular expansion of anterior aorta. Supports heart in pumping blood to anterior region of head.
(syn. accessory heart) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) In circulatory system, small, muscular expansion of anterior aorta. Located at border of cephalon and pereon; supports heart in pumping blood to anterior region of head.
(syn. accessory heart) [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) In circulatory system, muscular expansion of anterior aorta. Supports heart in pumping blood to anterior region of head.
(syn. anterior heart, frontal heart) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) In circulatory system, muscular expansion of anterior aorta. Supports heart in pumping blood to anterior region of head. [Stachowitsch, 1992]

Cordate

(Taxon-specific: Order Isopoda) Heart shaped in outline. [Kensley and Schotte, 1989]

Cormopod

See: Thoracopod [Martin, 2005]
See thoracopod. [McLaughlin, 1980]

Cormus

See: Thorax [Martin, 2005]

Cornea

Anterior part of carapace, including ocular peduncles, based on Munidopsis. [Baba, 2005]
(Figure only.) [Baba, 2005]
A transparent horny membrane forming the distal covering of the eye. [Ingle, 1980]
Faceted portion of the eye. [Butler, T. H.]
Faceted, usually pigmented portion of the eye (Fig. 3A). [Perez Farfante and Kensley, 1997]
Facetted and pigmented part of eyestalk. [Poore, 2004]
The faceted portion of the eye. [Chace and Hobbs, 1969]
The terminal cap of the eye, faceted except in most troglobites. [Hobbs, Hobbs, and Daniel 1977]
Transparent cuticle covering ommatidia of compound eye. [Moore and McCormick, 1969]
Transparent cuticle covering ommatidia of compound eye. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Transparent cuticle covering ommatidia of each eye. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Outermost layer of compound eye; may be divided into upper and lower units. (bilobed, cylindrical, globular, subglobular, laterally expanded; at right angle to stalk, oblique on stalk). [Stachowitsch, 1992]

Corneous

Structures that are horny (sclerified), particularly as related to reproductive appendages (modified first pleopod) of first form males. [Hobbs and Jass, 1988]

Corpus

(Taxon-specific: Subclass Copepoda) The massive proximal part of the subchelate maxilliped in some parasitic copepods, corresponding either to the basis or fused basis plus syncoxa. [Boxshall and Halsey, 2004]

Corpus mandibulae

See: Mandible body [Martin, 2005]
See mandible body. [McLaughlin, 1980]

Costa

(Taxon-specific: Class Ostracoda) Type of valve sculpture: prominent rib. Also used as synonym for carina. [Stachowitsch, 1992]

Coupling seta

(Taxon-specific: Order Isopoda) One in a series of cuticular projections on inner branch (endopod) of maxilliped or on medial margin of pleopods; serves to hook maxilliped or pleopod to its opposite member.
(syn. coupling hook) [Stachowitsch, 1992]

Coupling spine

Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) When present, coupling spines (or hooks) occur on the maxillipedal endites and pleopodal peduncles, and serve to lock the opposing appendages together, allowing them to function as a single unit. [Wetzer et al. 1997]

Coxa

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
Article 1 of thoracic and abdominal appendages. [Holdich and Jones, 1983]
First article of limb, usually short. [Poore, 2004]
First or proximal article of leg or maxilliped.
(syn. coxopodite) [Williams, 1984]
First or proximal podomere of a typically 7-segmented appendage (Fig. 3C).
(pl. coxae) [Perez Farfante and Kensley, 1997]
First or proximal segment of a typically 7-segmented apendage.
(pl. coxae) [Butler, T. H.]
Proximal (first) segment of segmented appendage. [Hobbs and Jass, 1988]
Segment of appendage adjoining sternite, except in forms having precoxa.
(syn. coxopodite) [McLaughlin, 1980]
Segment of limb directly attached to sternite of body (except rarely in forms having distinguishable precoxal segment).
(syn. coxopod(ite)) [Moore and McCormick, 1969]
Seventh segment of a pereiopod, counted from the distal end. [Ingle, 1983]
The basal podomere of a limb (Fig. 1). [Warner, 1977]
The first (proximal) segment of a segmented appendage. [Hobbs, Hobbs, and Daniel 1977]
The first or basal segment of a thoracic appendage.
See: Pereopod [Wilson, 1989]
The first or proximal segment of a typically 7-segmented appendage.
(pl. coxae) [Chace and Hobbs, 1969]
(Taxon-specific: Class Cephalocarida) Protopod. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) First segment of thoracopod (maxillipeds and pereopods) or pleopod. May be more or less fused with ventral surface (sternites) of body. Coxae of second maxillipeds fused to one another.
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) First of seven segments (coxa, basis, ischium, mercus, carpus, propodus, dactylus) of thoracopod. Bears well-developed epipod in maxillipeds (= first thoracopods) and may be indistinct or absent in chelipeds (= second thoracopods).
(syn. coxopodite)
See: Precoxa [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) First, most proximal segment of appendage; forms protopod together with following segment (basis). Depending on appendage, coxa may bear opening of antennal gland, epipodite, gill (podobranch), or gonopore.
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) First of basically seven segments (coxa, basis, ischium, merus, carpus, propodus, dactylus) of thoracopod; typically developed as large, immovable coxal plate.
(syn. coxapodite) [Stachowitsch, 1992]
Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Basal article of an appendage, attached to sternite, sometimes expanded into a lateral coxal plate. [Kensley and Schotte, 1989]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Basal article of an appendage. [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) First segment of pereopod; often expanded to form projecting coxal plate.
(syn. coxapodite) [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) First of two segments (coxa, basis) of proximal part (protopod) of appendage.
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Second segment of thoracic appendage (thoracopod). Also interpreted as being first segment (forming fused precoxa and coxa).
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Most proximal segment of appendage. Gonopores located on coxae of sixth (female) or eighth (male) thoracopods. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) In thoracopod, second of three segments (precoxa, coax, basis) of protopod; may also be applied to segment of antennule.
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) First, most proximal segment of appendage. Typically forms protopod together with following segment (basis). Generally specified only in maxillules (where it bears endites and exites) and pereopods (coxae of opposed limbs united).
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The middle segment of the 3-segmented protopod of postmandibular limbs, the proximal segment of the 2-segmented protopod of the antenna and mandible. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) The middle segment of the protopod, proximal to the basis and distal to the praecoxa, with a single setose endite; the mandibular gnathobase of copepods includes the coxal endite with its single seta (see basis and praecoxa). [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Mystacocarida) Protopod. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) First, most proximal segment of appendage; typically forms protopod together with following segment (basis). Forms ganthobase in mandibles. (See also precoxa).
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Proximal part of divided protopod (separated from basis by suture).
See: Protopod [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Superorder Syncarida) First of two segments (coxa, basis) of proximal part (protopod) of appendage. May bear lateral lobes (endites, epipods).
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) First of two segments (coxa, basis) of proximal part (protopod) of appendage.
(syn. coxopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) First, most proximal segment of appendage; forms protopod together with following segment (basis). Typically specified only when referring to thoracopods. Coxae of maxillae bear endites, those of thoracopods bear gills (epipodites), with coxae of second and seventh thoracopods (occasionally more) containing photophores.
(syn. coxapodite) [Stachowitsch, 1992]

Coxal endite

Lobe produced from inner margin of coxa. [McLaughlin, 1980]

Coxal exite

Lobe produced from outer margin of coxa.
(syn. coxepipod) [McLaughlin, 1980]

Coxal gill

(Taxon-specific: Order Amphipoda) Respiratory structure projecting from basal segment (coxa) of pereon appendage (peropod); consists of modified epipod. Six pairs of coxal gills (on pereon segments 2-8) represent full complement. (digitiform, foliate, sac-like; walls: simple = smooth, convoluted, pleated).
(syn. branchia)
See: Accessory gill, Sternal gill [Stachowitsch, 1992]

Coxal gland

(Taxon-specific: Order Amphipoda) Segmentally arranged series of small excretory structures, one pair in each somite (pereonite) of pereon as well as in first four abdominal somites. [Stachowitsch, 1992]

Coxal plate

Lateral expansion of coxa broadly joined to lateral mergin of tergite. [McLaughlin, 1980]
Lateral expansion of pereiopod coxa joined broadly to lateral margins of tergites. [Moore and McCormick, 1969]
Pereopodal coxae that are expanded as lateral side plates in some of the more derived groups of isopods and in some amphipods. [Brusca and Brusca, 2002]
(Taxon-specific: Order Amphipoda) Modification of proximal segment (coxa) of appendage (e.g., pereopod) into immovable, plate-like structure. Serves protect gills and accentuates laterally compressed shape of body, (contiguous, discontiguous; bilobed, rectangular, rounded, spiniform; margin: setose, serrate, smooth; ornamentation: setose, with ridges, spines, tubercles). [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Coxae of the pereopods laterally expanded into flattened lamellar structures extending freely (as "plates") to overhang the coxa-basis hinge of the leg. [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Lateral extension of proximal segment (coxa) of pereopod; may be fused to body wall.
(syn. epimere) [Stachowitsch, 1992]

Coxal spine

Spine projecting from the coxa of a thoracic appendage. [Perez Farfante and Kensley, 1997]

Coxepipod

Coxal exite. [Moore and McCormick, 1969]
See coxal exite. [McLaughlin, 1980]

Coxicerite

(Taxon-specific: Order Decapoda) In antenna, term applied to first of two segments (coxicerite, basicerite) of peduncle. [Stachowitsch, 1992]

Coxite

See: Protopod [Martin, 2005]

Coxobasis

(Taxon-specific: Subclass Copepoda) A compound protopodal segment representing coxa plus basis. [Boxshall and Halsey, 2004]

Coxopod

See: Coxa [Martin, 2005]

Crenulate

(Taxon-specific: Order Isopoda) Having a scalloped edge with rounded teeth, usually used to refer to the margin of a structure. [Kensley and Schotte, 1989]

Crested

With elevated and irregular or toothed ridge. [Butler, T. H.]

Crista

(Taxon-specific: Subclass Copepoda) A group of small spinules or setules on the apex of the maxilla of some siphonostomatoids. [Boxshall and Halsey, 2004]

Crista dentata

(Taxon-specific: Order Decapoda) In third maxilliped, toothed median margin of third segment (ischium). [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Toothed crest on ischium of 3rd maxilliped. [McLaughlin, 1980]

Cristate

Sharply emarginate. [Ingle, 1980]

Crop

(Taxon-specific: Subclass Branchiura) Midgut. [Stachowitsch, 1992]

Crustaceans

Members of the superclass Crustacea of the phylum Arthropoda. Examples are shrimps, lobsters, crabs, amphipods, copepods, isopods, and barnacles. [Bliss, 1982]

Cryptoniscus

Planktonic larval stage of epicaridean isopod with pereopods modified as holdfasts. Stage at which larva seeks a permanent host. [McLaughlin, 1980]
(Taxon-specific: Order Isopoda) Third of three larval stages (epicaridium, microniscus, cryptoniscus) in certain parasitic isopods. Free-living, more elongate, and characterized by seven pairs of grasping pereopods. Swims by means of antennae pleopods and attaches to final host. [Stachowitsch, 1992]

Ctenopod

Appendage (cirrus) usually with long paired setae on segments of lesser curvature and few setae distally on each articulation of greater curvature. [McLaughlin, 1980]
In cirripeds, appendage where rami of cirrus have setae arranged in linear series along lesser curvature , like a comb (cf. acanthopod, lasiopod). [Moore and McCormick, 1969]

Cuspate

Having a sclerotized surface or margin with one or more rounded projections. [Wilson, 1989]

Cuspidate seta

Shaft varying from thin to stout; setules prominent and often extending post-annularly, setules with setulettes; setules sometimes grading into denticles and setae may grade into plumodenticulate type; socket usually prominent; annulus usually apparent; pore usually present. [Ingle, 1992]

Cuticle

(Taxon-specific: Order Anostraca) Noncellular, multilayered structure forming outer layer of body and lining esophagus and hindgut; relatively thin and not calcified. Secreted by epidermis. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Noncellular, multilayered, relatively thick layer forming exoskeleton and endoskeleton and lining foregut and hindgut. Secreted by epidermis. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Noncellular, multilayered layer forming exoskeleton and lining foregut and hindgut. (smooth, spinose, with plate-like projections). [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Noncellular, multilayered, relatively thick layer forming exoskeleton and lining both foregut and hindgut. Secreted by epidermis. Forms plate-like structures (cephalic shield, sternites, tergites). [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Noncellular, multilayered structure forming outer layer of body and lining foregut (stomodeum) and hindgut (proctodeum); relatively thin and pigment-free. Secreted by epidermis. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Noncellular, multilayered, relatively thick layer forming valved, endoskeleton, and exoskeleton, and lining foregut and hindgut. Secreted by epidermis. [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Noncellular, multilayered outer layer of body; secreted by epidermis and equipped with numerous pores and sensory organs. Also lines foregut and joining dorsal brain to ventral nerve cords. [Stachowitsch, 1992]

Cuticular

Of the cuticle. [Wilson, 1989]
Pertaining to, or part of the integument or shell; structurally, cuticle is complex, made up of four layers of differing chemical composition. [Butler, T. H.]

Cuticular combs

Tiny, arc-shaped or linear groups of cuticular spines, most easily Seen on the distal parts of the mandibular palp. They may occur elsewhere on the cephalic appendages. [Wilson, 1989]

Cuticular organ

The paired female copulatory organ of Asellota, found either ventrally or on the anterior dorsal margin of pereonite 5. [Wilson, 1989]

Cycladiformes

Conchostracan carapaces having dorsal margin of valves forming obtuse with posterior margin. [Moore and McCormick, 1969]
(Taxon-specific: Order Diplostraca) Carapace with dorsal margin of valve forming obtuse angle with posterior margin. [McLaughlin, 1980]

Cyclomorph

(Taxon-specific: Order Cladocera) Any one of variously modified individuals in a population. These modifications are seasonal and generally involve the head (development of helmet) or changes in eye size or carapace spine length. [Stachowitsch, 1992]

Cyclomorphism

Seasonal changes in body form through succeeding generations of parthenogenetically produced individuals. [Brusca and Brusca, 2002]

Cyclops stage

Post-metanaupliar stage in ontogeny in some copepods. [Moore and McCormick, 1969]
(Taxon-specific: Subclass Copepoda) Post-metanaupliar stage. [McLaughlin, 1980]

Cyprid

(Taxon-specific: Subclass Cirripedia) Cypris larva. [Stachowitsch, 1992]

Cypris adductor muscle

Transverse muscle that attaches the two sides together in the cypris larva of cirripedes. [Brusca and Brusca, 2002]

Cypris larva

"Bivalved" larval type following the naupliar stage in most cirripedes. [Brusca and Brusca, 2002]
Unique larval stage that follows the nauplius stage in cirripedes. [Brusca and Brusca, 2002]
(Taxon-specific: Subclass Cirripedia) Final larval stage, common to all cirripeds, characterized by bivalved carapace, compound eyes, prehensile antennules, and series of locomotory thoracic appendages (cirri). (See also nauplius).
(syn. cyprid, cyprid larva) [Stachowitsch, 1992]

Cypris stage

Bivalve larval stage. [McLaughlin, 1980]
Ostracode-like larval stage (e.g., Cirripedia). [Moore and McCormick, 1969]

Cyrtopia

(Taxon-specific: Order Euphausiacea) Furcilia. [Stachowitsch, 1992]

Cyrtopia stage

Fifth larval stage in euphausiaceans in which antennae no longer serve for locomotion. [Moore and McCormick, 1969]
(Taxon-specific: Order Euphausiacea) Formerly considered 5th larval stage with antennae no longer used in locomotion; currently included in furcilia stage. [McLaughlin, 1980]

Dactyl

Article 7 of pereopod (article six of cheliped). [Holdich and Jones, 1983]
Diastalmost segment of limb.
(syn. dactylopod(ite)) [Moore and McCormick, 1969]
Distalmost segment of usually 7-segmented appendage; smaller, mesially situated, and moveable part of chela (moveable finger). (see Fig. 14) [Hobbs and Jass, 1988]
Terminal or distal article of leg; movable finger of cheliped.
(syn. dactylus or dactylopodite) [Williams, 1984]
Terminal podomere of a typically 7-segmented appendage (Fig. 3C). [Perez Farfante and Kensley, 1997]
The distalmost segment of a usually 7-segmented appendage. [Hobbs, Hobbs, and Daniel 1977]
The first segment of a pereiopod, counted from the distal end. [Ingle, 1983]
The most distal segment of a limb. [Mauchline, 1984]
The seventh or distal segment of a thoracic appendage, bearing one or more distal claws.
See: Pereopod [Wilson, 1989]
The seventh or terminal segment of a typically 7-segment appendage. [Chace and Hobbs, 1969]
The terminal podomere of the endopod of a limb (Figs. 1, 2). [Warner, 1977]
(Taxon-specific: Class Cephalocarida) Claw. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Seventh and terminal segment of thoracic appendage (thoracopod). In first five thoracopods, folded back on propodus to form subchela. Particularly well developed on second thoracopod to form raptorial claw. (inner margin: armed, unarmed; outer margin: curved, sinuate; base: inflated, no inflated).
(syn. dactylus) [Stachowitsch, 1992]

Dactylus

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
Entire animal, right appendages omitted, dorsal view, based on Munida. [Baba, 2005]
(Figure only.) [Baba, 2005]
Endopod of Mxp 3, lateral; and endopod of Mxp 3, including basal 2 articles, distal articles omitted, central. Based on Munidopsis. [Baba, 2005]
(Figure only.) [Baba, 2005]
Seventh article of limb (last article interacting with fixed finger to form chela in chelate limb).
(syn. dactyl) [Poore, 2004]
Seventh or terminal segment of a typically 7-segmented appendage.
(pl. dactyli) [Butler, T. H.]
Ultimate segment of thoracopod.
(syn. dactylopodite) [McLaughlin, 1980]
(Taxon-specific: Order Cumacea) Fifth and most distal of five segments (ischium, merus, carpus, propodus, dactylus) of endopod or thoracopod (maxillipeds and pereopods).
(syn. dactyl) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Seventh, most distal of basically seven segments (coxa, basis, ischium, mercus, capus, propodus, dactylus) of thoracopod. In second pair of thoracopods (= chelipeds or first pereopods) forms movable distal element in chela or subchela.
(syn. dactyl) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Seventh and terminal segment of appendage (thoracopod). Follows propodus and may serve as distal element in subchela or as movable finger in chela. (simple, many jointed; bifurcate, curved, falcate, falciform, obtuse, rounded, sharply pointed, spatulate, subacute, straight; ciliate, furred, grooved, hairy, smooth, spinose).
(syn. dactyl, dactylopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Seventh and most distal of basically seven segments (coxa, basis, ischium, merus, carpus, propodus, dactylus) thoracopod. In gnathopod, may form moveable distal element in chela or subchela. (oriented anteriorly/posteriorly).
(syn. dactyl) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Seventh and terminal segment of perepod. In gnathopod, may form movable distal element in subchela. (biunguiculate, triunguiculate).
(syn. dactyl, dactylopodite) [Stachowitsch, 1992]
Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Terminal (7th) article of a pereopod or thoracic appendage. [Kensley and Schotte, 1989]
(Taxon-specific: Order Mysida) Sixth and most distal segment (preischium, ischium, merus, carpus, propodus, dactylus) of inner branch (endopod) of thoracopod. Usually minute, with claw. May form movable distal element in subchela.
(syn. dactyl) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Sixth, most distal segment (preischium, ischium, merus, carpus, propodus, dactylus) of inner branch (endopod) of thoracopod.
(syn. dactyl) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Fifth and most distal of basically five segments (ischium, merus, carpus, propodus, dactylus) of inner branch (endopod) of thoracopod.
(syn. dactyl) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Seventh segment of thoracopod (fifth or last segment of endopod); may serve as movable element in terminal pincer (chela).
(syn. dactyl) [Stachowitsch, 1992]

Decapod crustaceans

Members of the order decapoda, class Malacostraca, superclass Crustacea, phylum Arthropoda; have five pairs of thoracic legs. Examples are shrimps, lobsters, crabs, and hermit crabs. [Bliss, 1982]

Decapodid stage

(Taxon-specific: Order Decapoda) Postlarva. [Stachowitsch, 1992]

Decurved

Curved downward. [Butler, T. H.]

Deflected

Bent or turned, usually abruptly. [Butler, T. H.]

Deflected front

Broadly downturned front margin of carapace in some decapods. [McLaughlin, 1980]

Deflexed front

Broadly downturned front marginal part of carapace in some decapods. [Moore and McCormick, 1969]

Delayed development

A moulting sequence producing one or more larval forms showing little or no morphological progress towards a more advanced stage. [Ingle, 1992]

Dendrobranch

A type of decapod gill bearing two principal branches off the main axis, each of which is divided into multiple secondary branches. [Brusca and Brusca, 2002]
Type of gill having tubes divided into arborescent bundles. [Moore and McCormick, 1969]
Type of gill with lamellae divided into arborescent bundles. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Type of gill whose axis bears series of highly subdivided branches.
See: Phyllobranch, Trichobranch [Stachowitsch, 1992]

Dendrobranchiate

(noun) A decapod bearing dendrobranch gills, or (adjective) the condition of having dendrobranch gills. [Brusca and Brusca, 2002]

Dendrobranchiate gill

Gill with paired primary branches subdivided. [Poore, 2004]
One in which the paired primary branches are subdivided, sometimes highly so. [Perez Farfante and Kensley, 1997]

Dentate

With sharp spines directed outward from margins. [Butler, T. H.]
(Taxon-specific: Order Isopoda) Edged with teeth. [Kensley and Schotte, 1989]

Denticle

(Taxon-specific: Order Isopoda) A small tooth. [Kensley and Schotte, 1989]
(Taxon-specific: Subclass Copepoda) A solid extension of the epicuticle of a segment (see seta and setule). [Ferrari and Dahms, in press]

Denticulate

A surface invested with denticulettes. [Ingle, 1992]
Having denticles. [Wilson, 1989]
(Taxon-specific: Order Isopoda) Having fine teeth. [Kensley and Schotte, 1989]

Denticulate seta

A generally robust seta with either a row of denticles or a group of distal denticles. [Wilson, 1989]

Denticule

A non-articulated extension of the shaft of a seta or spine. [Watling, 1989]
A short, pointed, tooth-like projection of the cuticle. [Wilson, 1989]
In cirripeds (Balanomorpha), primary or secondary toothlet on sutural edge of radius of compartment plate or opposed buttress of adjoining plate, serving to strengthen articulation of plates. [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) One in a series of small, tooth-like projections along postabdomen. Number, position, and relative size are of taxonomic importance. (equal, subequal; smooth, serrate; lateral, marginal). [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) One of numerous smaller tooth-like projections between larger teeth on telson margin; according to position one may distinguish submedian, intermediate, and lateral denticles. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Small, tooth-like projection on outer surface or hinge of valve. [Stachowitsch, 1992]

Depressed

Flattened from above downwards, or dorsoventrally. [Butler, T. H.]

Depressor muscle

In Cirripedia (Balanomorpha), muscle inserted at basicarnial angle of tergum, for which depressor muscle crests are usually developed. [Moore and McCormick, 1969]
Muscle inserted at basicarinal angle of tergum (balanomorph Cirripedia). [McLaughlin, 1980]
The muscle which moves the limb downwards by rotating it about the CB joint. [Warner, 1977]
(Taxon-specific: Subclass Cirripedia) In stalked barnacle, one of several paired muscles spanning from tergum and scutum to basis; serves in closing aperture. [Stachowitsch, 1992]

Depressor muscle crests

In cirripeds (Balanomorpha), elevated denticles on interior of tergum near basicarinal angle for attachment of depressor muscles (crests may extend apically). [Moore and McCormick, 1969]
(Taxon-specific: Subclass Cirripedia) Barnacle plate feature: on inner surface of tergum in unstalked form, elevated denticles or ridges near basicarinal angle. Serves as site of attachment of depressor muscle. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Elevated denticles or ridges on inner surface of tergum near basicarinal angle for attachment of depressor muscles (balanomorph Cirripedia). [McLaughlin, 1980]

Depressor muscle, lateral

In Cirripedia (Balanomorpha), muscle inserted on basitergal angle of scutum, for which lateral depressor muscle pit, depression or crests may develop. [Moore and McCormick, 1969]

Dermal

See: Cuticular [Butler, T. H.]

Dermal gland

Cell or concentration of cells in epidermis traversed by canals communicating with surface through fine ducts. [McLaughlin, 1980]
Single cell or concentration of cells in epidermis of body and limbs, traversed by canals and communicating with surface by fine ducts, their functions various and possibly corresponding to cement glands of cirripeds. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) One of numerous glands in epidermis underlying cuticle; opens to exterior through long ducts traversing cuticle. [Stachowitsch, 1992]

Descending

Directed downward. [Butler, T. H.]

Descending aorta

(Taxon-specific: Order Mysida) Major unpaired blood vessel arising ventrally near posterior end of heart. Variously branched ventrally. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Aorta. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Major blood vessel arising from ventral surface of heart. Extends around gonads and branches above ganglia of thorax into an anteriorly and posteriorly directed artery (sternal and abdominal arteries). (paired, unpaired). [Stachowitsch, 1992]

Detritus

Non-living particulate organic matter inhabited by decomposer organisms; also, including dissolved carbon-containing substances excreted by plants and animals as well as soluble organic materials released from decaying plant and animal tissues. [Hobbs and Jass, 1988]

Deuterocerebrum

See: Mesocerebrum [Martin, 2005]
One of two anterior dorsal supraesophageal ganglia in the crustacean brain; receives the antennulary nerves. [Brusca and Brusca, 2002]
See mesocerebrum. [McLaughlin, 1980]
(Taxon-specific: Order Cladocera) Supraesophageal ganglion. [Stachowitsch, 1992]

Deutocerebrum

(Taxon-specific: Order Decapoda) Supraesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Brain. [Stachowitsch, 1992]

Diacresis

Transverse groove on posterior of exopod (rarely also endopod) of uropod appendage, in some forms dividing exopod into 2 movably connected parts. [Moore and McCormick, 1969]
Transverse groove on posterior part of exopod (also rarely of endopod) of uropod; sometimes dividing exopod into 2 movable parts. [McLaughlin, 1980]

Diaeresis

(Taxon-specific: Order Decapoda) Transverse groove across outer branch (exopod) of uropod; may divide exopod into two movable parts. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Transverse suture superficially subdividing one or both branched of uropod, or antennal scale. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) In anaspidacean, transverse suture superficially dividing outer branch (exopod) of uropod. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Transverse groove across outer branch (exopod) of uropod in certain euphausiaceans. [Stachowitsch, 1992]

Diapause

A period of suspended development. [Ingle, 1983]
Extreme state of anaerobic quiescence (seen in encysted embryos of some large-bodied branchiopods and eggs or cysts of some copepods). [Brusca and Brusca, 2002]
(Taxon-specific: Subclass Copepoda) A significant period of quiescence during development. [Ferrari and Dahms, in press]

Digestive cecum

(Taxon-specific: Order Cladocera) One of two lateral outpocketings of midgut; located in head posterior to border of esophagus and midgut. An additional unpaired cecum may open into posterior end of digestive tract.
(syn. cecum, hepatic cecum, midgut diverticulum) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) One of two lateral outpocketings of midgut near border of esophagus and midgut. Highly branched, with lobe-shaped branches extending ventrally and dorsally and anterior part of head.
(syn. caecum) [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Dorsal cecum, lateral cecum. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) One of up to several pairs of outpocketings of anterior region of midgut.
(syn. digestive gland, gut diverticulum, hepatic cecum) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Pair of elongate digestive glands opening into digestive tract at border of stomach and midgut. Extends posteriorly to end of abdomen.
(syn. hepatopancreas) [Stachowitsch, 1992]

Digestive diverticulum

(Taxon-specific: Order Tanaidacea) One or two pairs of digestive glands opening into digestive tract at border of stomach and midgut. [Stachowitsch, 1992]

Digestive gland

(Taxon-specific: Order Decapoda) Hepatic cecum. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Pair of large glands, one originating from each side of pyloric stomach and extending along midgut. Fills most of body, giving rise to pair of lateral pouches in posterior four throacomeres, in all pleomeres, and branching into telson.
(syn. Digestive cecum, cecum) [Stachowitsch, 1992]

Digitiform

(Taxon-specific: Order Isopoda) Fingerlike. [Kensley and Schotte, 1989]

Direct development

See Epimorphic development [Ingle, 1992]

Distad

(Taxon-specific: Subclass Copepoda) Toward the distal end of a limb. [Ferrari and Dahms, in press]

Distal

Away from body mid-line; toward apex (tips) of appendages. [Hobbs and Jass, 1988]
Direction away from central part of body; opposite of proximal. [Moore and McCormick, 1969]
Part of structure farthest from midline of body or base of attachment; opposed to proximal. [McLaughlin, 1980]
Situated away from the base or point of attachment. [Butler, T. H.]
(Taxon-specific: Order Isopoda) Situated away from the base or point of origin or attachment. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Situated away from the base or point of origin or attachment. [Wetzer et al. 1997]

Distal fold

Distal pleat in the dorsolateral lobule of the petasma. [Perez Farfante and Kensley, 1997]

Distolateral

Outer side of margin of an appendage, e.g., uropod. [Butler, T. H.]

Distolateral projection

Distolateral, ventrally inclined projection or spur of the basis of the endopod of the male second pleopod. [Perez Farfante and Kensley, 1997]

Distomedian projection

Distal, relatively narrow extension of the dorsomedian lobule of the petasma. [Perez Farfante and Kensley, 1997]

Distoventral projection

Outer distal flap articulating with the distal extremity of ventrolateral lobule of petasma in members of the genus Metapenaeopsis. [Perez Farfante and Kensley, 1997]

Diverticulum

(Taxon-specific: Order Anostraca) Midgut diverticulum. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) One of two simple glandular outpocketings of digestive tract; located in head and opening into anterior region of midgut. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Midgut cecum. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Lateral midgut diverticulum, oviducal diverticulum. [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) One of a pair of lateral outpocketings of midgut in each trunk segment; each diverticulum extends into pleurite of segment. Diverticula become smaller toward posterior end of body and almost completely disappear in posterior-most region.
(syn. gut diverticulum) [Stachowitsch, 1992]

Domicillium

(Taxon-specific: Class Ostracoda) The volume between the two valves of the carapace and occupied by the soft body and limbs. [Cohen, Peterson, and Maddocks, in press]

Dorsad

Toward dorsal surface. [Butler, T. H.]

Dorsal

Of, or pertaining to, the back or upper surface. [Butler, T. H.]
Top or back of shrimp crayfish. [Hobbs and Jass, 1988]

Dorsal abdominal artery

(Taxon-specific: Order Decapoda) Dorsal aorta. [Stachowitsch, 1992]

Dorsal artery

(Taxon-specific: Order Decapoda) Major unpaired blood vessel arising from posterior end of heart. Extends to posterior end of abdomen and gives rise to series of segmental arteries in abdominal somites (pleomeres).
(syn. dorsal abdominal artery, posterior aorta, superior abdominal aorta) [Stachowitsch, 1992]

Dorsal cecum

(Taxon-specific: Order Mysida) Typically unpaired dorsal outpocketing of digestive tract at border of pyloric stomach and midgut. (paired, unpaired) (See also lateral cecum).
(syn. dorsal diverticulum) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) One of two small dorsal outpocketings of digestive tract at border of pyloric stomach and midgut.
See: Hepatic gland [Stachowitsch, 1992]

Dorsal keel

(Taxon-specific: Order Mysida) Keel. [Stachowitsch, 1992]

Dorsal organ

Poorly understood glandular-sensory structures (actually several different structures that may or may not be homologous) on the head of many crustaceans. [Brusca and Brusca, 2002]
Thickened glandular area of hypoderm of dorsal surface just behind head in various branchiopods, isopods, amphipods, mysidaceans, tanaidaceans, and syncarids, its function obscure. [Moore and McCormick, 1969]
Thickened glandular area of hypoderm on dorsal surface, usually in posterior of cephalon, sometimes in anterior part; not homologous in all taxa. [McLaughlin, 1980]
(Taxon-specific: Order Notostraca) Unpaired organ of unknown function located behind compound eyes on dorsal surface of carapace. (considerably behind eye tubercles, anterior part between eye tubercles; circular, somewhat triangular).
(syn. nuchal organ) [Stachowitsch, 1992]

Dorsal orifice

The distal opening of the sperm tube in the janiroidean male's first pleopod. [Wilson, 1989]

Dorsal oval

Dorsal region of carapace defined by linea thalassinica laterally, cervical groove posteriorly and oblique semicircle anteriorly (Thalassinidea). [Poore, 2004]

Dorsal pit

(Taxon-specific: Order Stomatopoda) Median pore. [Stachowitsch, 1992]

Dorsal plate

Spindle-shaped division of carapace in some astacidean decapods (Erymidae) intercalated in median suture; may be related to dorsal organ. [Moore and McCormick, 1969]
Spindle-shaped division of carapace intercalated with median suture in some decapods. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) Spindle-shaped division of carapace intercalated with median suture. [Stachowitsch, 1992]

Dorsal process

(Taxon-specific: Class Ostracoda) Dorsal forked projection of basal segment of maxillule. [Stachowitsch, 1992]

Dorsal spine

(Taxon-specific: Order Euphausiacea) Spine. [Stachowitsch, 1992]

Dorsolateral

Upper side of a structure. [Butler, T. H.]

Dorsolateral carina

Longitudinal ridge of dorsolateral region of carapace running dorsal to orbital region. [Perez Farfante and Kensley, 1997]

Dorsolateral lobule

Dorsal part of the lateral lobe of the petasma (Fig. 4B). [Perez Farfante and Kensley, 1997]

Dorsolateral sulcus

Longitudinal groove sometimes present close to the dorsomedian line of the sixth abdominal somite. [Perez Farfante and Kensley, 1997]

Dorsolaterally

From upper to lower surface or margin. [Butler, T. H.]

Dorsomedian carina

Ridge extending along the middorsal line of the abdominal somites (Fig. 1). [Perez Farfante and Kensley, 1997]

Dorsomedian groove

(Taxon-specific: Order Decapoda) See: Carapace grooves e [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) On carapace, longitudinal dorsomedian groove extending from tip of rostrum to posterior margin. [Stachowitsch, 1992]

Dorsomedian lobule

Mesial part of the medial lobe of the petasma (Fig. 4B). [Perez Farfante and Kensley, 1997]

Dorsoventral axis

(Taxon-specific: Subclass Copepoda) An imaginary line through the surface of the body opposite the limbs to the surface bearing the limbs; the terms 'lateral' and 'medial' often are used in place of 'dorsal' and 'ventral' in descriptions of appendages. [Ferrari and Dahms, in press]

Dorsoventral muscle

(Taxon-specific: Class Cephalocarida) One of three pairs of muscles extending in a dorsoventral direction in each trunk segment. [Stachowitsch, 1992]

Dorsoventralis posterior

Important muscle in crayfish and other decapods connecting head apodemes with internal surface of carapace just behind cervical groove. [Moore and McCormick, 1969]
Prominent muscle connecting head apodemes with inner surface of carapace posterior to cervical groove in many decapods. [McLaughlin, 1980]

Dorsoventralis posterior muscle

(Taxon-specific: Order Decapoda) In cephalothorax, prominent muscle extending from head apodemes to carapace, where it inserts posterior to cervical groove. [Stachowitsch, 1992]

Dorsum

The dorsal surface of a body segment.
(pl. dorsa) [Wilson, 1989]
(Taxon-specific: Class Ostracoda) In carapace, more or less flattened area to each side of hinge; delimited from lateral surface by angle in valve. [Stachowitsch, 1992]

Doublure

Reflexed ventral continuation of carapace integument. [Moore and McCormick, 1969]
(Taxon-specific: Order Stomatopoda) Reflected margin of carapace. [McLaughlin, 1980]

Duplicature

(Taxon-specific: Class Ostracoda) Along inner margin of valve, thickened, calcified section of inner lamella. Space between outer lamella and duplicature is termed vestibule. Medially directed surface of duplicature contacts opposite member when carapace is closed and may bear various ridges and grooves. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) That part of border of shell with calcareous peripheral part of inner lamina in contact with, or separated by vestibule from, outer lamina, generally narrow, sometimes extensive. [McLaughlin, 1980]

Dwarf male

(Taxon-specific: Subclass Cirripedia) In barnacle, term applied to relatively small male attached to female individual. (See also complemental male). [Stachowitsch, 1992]

Ecdysis

Act of molting the integument. [McLaughlin, 1980]
In crustaceans, the shedding of the old exoskeleton, or shell. [Bliss, 1982]
Moulting; the shedding of the old cuticle. [Ingle, 1983]
see Molting. [Butler, T. H.]
(Taxon-specific: Order Isopoda) Molting of the integument. [Kensley and Schotte, 1989]
(Taxon-specific: Subclass Copepoda) The process of shedding the exoskeleton during molting. [Ferrari and Dahms, in press]

Ectosoma

(Taxon-specific: Subclass Copepoda) That part of the body of a mesoparasite that is outside the host. [Boxshall and Halsey, 2004]

Edge

(Taxon-specific: Class Ostracoda) Outermost line of contact between two valves when carapace is closed (includes hinge region). Free edge refers to outermost line of contact of valves excluding hinge region. [Stachowitsch, 1992]

Efferent branchial channels

Pair of channels between ridges, venting branchial cavity and opening lateral to endostome (some Brachyura). [Poore, 2004]

Efferent channels

Channels through which water passes from gills. Openings at sides of endostome, except in Section Oxystomata in which they open at middle of endostome. [Williams, 1984]
Passageways through which water moves away from gills and out of branchial region. [Moore and McCormick, 1969]
Passageways through which water moves away from gills and out of branchial region. [McLaughlin, 1980]

Efferent respiratory channels

Channels through which water passes from the gills and which open at the dorso-external (in the Brachyrhyncha) or at the middle (in the Oxyrhyncha) of the endostome margin.
(syn. efferent branchial channels) [Ingle, 1980]
(Taxon-specific: Order Decapoda) Opening through which water exits from branchial chamber under carapace. Typically applied to more restricted opening in crab-like (brachyuran) decapod; located anteriorly on each side of endostome.
(syn. efferent branchial channel) [Stachowitsch, 1992]

Egestion

Process of eliminating indigestible material, usually by way of the anus. [Butler, T. H.]

Egg

Spheroidal body produced by ovary of female, containing embryo and yolk as food supply. [Butler, T. H.]

Egg nauplius

Term referring to the naupliar larval stage when passed through as part of a longer period of embryonic development (or a long brood period) in species with yolky eggs. [Brusca and Brusca, 2002]

Egg sac

(Taxon-specific: Subclass Copepoda) A batch of one or more eggs contained within a sac-like membrane that remains attached to the genital opening(s); typically paired. [Boxshall and Halsey, 2004]

Egg string

(Taxon-specific: Subclass Copepoda) Elongate ovisac characteristic of certain parasitic copepods. [Stachowitsch, 1992]

Egg-bearing

see Ovigerous. [Butler, T. H.]

Eighth limb

See copulatory limb.
See: Copulatory limbs [Cohen, Peterson, and Maddocks, in press]

Ejaculatory duct

(Taxon-specific: Order Decapoda) In male reproductive system, muscular terminal end of vas deferens. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) In male reproductive system, expanded terminal section of vas deferens. Opens to exterior on penis. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Unpaired terminal end of male reproductive system; formed by merger of vasa deferentia. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) In male reproductive system, posteriormost section of vas deferens; opens to exterior via gonopore on first abdominal segment (genital somite). [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) In male reproductive system, modified distal end of each vas deferens. Typically associated with penis. [Stachowitsch, 1992]

Elaphocaris

(Taxon-specific: Order Decapoda) Protozoea. [Stachowitsch, 1992]

Element

(Taxon-specific: Subclass Copepoda) A serially repeated component or part of a segment, e.g. the dorsal formation seta, the ventral formation seta or the finishing arthrodial membrane. [Ferrari and Dahms, in press]

Elongate

Lengthened, longer than deep or wide. [Butler, T. H.]

Elytra

(Taxon-specific: Subclass Copepoda) Wing-like expansions of the dorsal or dorsolateral surface of postcephalic trunk somites in some siphonostomatoids. [Boxshall and Halsey, 2004]

Emarginate

Having a slight notch or indentation. [Butler, T. H.]
(Taxon-specific: Order Isopoda) Having the margin concave. [Kensley and Schotte, 1989]

End sac

(Taxon-specific: Order Decapoda) Proximal section of antennal gland. Typically divided into saccule and labyrinth; opens into bladder (occasionally via excretory tubule). [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Expanded proximal section of each maxillary gland. Opens to exterior via coiled duct. [Stachowitsch, 1992]

Endite

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
A mesial lobe-like extension of a podomere or such an extension from the axial part of an unsegmented appendage. [Hobbs, Hobbs, and Daniel 1977]
A non-specific term to describe a branch of an appendage. [Ingle, 1983]
Inwardly (medially) directed lobe of first segments of maxillules, maxillae, and maxillipeds. Endites of maxillules may function as auxiliary mandibles. (arcuate, cone-like, digitiform, double-crested, lobe-like, subtriangular). [Stachowitsch, 1992]
Inwardly (medially) directed lobe of precoxa, coxa, basis, or ischium. [Moore and McCormick, 1969]
Inwardly (medially) directed lobe of precoxa, coxa, basis, or ischium. [McLaughlin, 1980]
Inwardly directed projection arising from the basis of an appendage. [Holdich and Jones, 1983]
Lobe of several proximal podomeres of various appendages. [Perez Farfante and Kensley, 1997]
Lobe, usually mesial, of proximal articles of limbs, especially mouthparts. [Poore, 2004]
Medial outgrowth of the protopod. [Brusca and Brusca, 2002]
Mesial lobelike extension of podomere or of axial part of unsegmented appendage. [Hobbs and Jass, 1988]
(Taxon-specific: Order Cladocera) Inwardly (medially) directed, setose lobe of basal part (protopod) of trunk appendage. First endite typically well delimited, the following endites increasingly incorporated into endopod. [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) One of five inwardly (medially) directed setose lobes of basal segment (protopod) of thoracic or abdominal appendage. Most distal (sixth) endite often termed endopod. Elongate endites of first thoracopod are termed flagella and may project beyond carapace margin. (lobelike, filiform). [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) One of five inwardly (medially) directed, setose lobes of basal part (protopod) of trunk appendage. Most distal (sixth) endite often termed endopod, while fifth may be modified as palp (especially in male). [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) In thoracic appendage (thoracopod), one of basically five inwardly (medially) directed, setose lobes of protopod. Serves in feeding. (distinct, partially fused). [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) One of up to several inwardly (medially) directed, setose lobes of protopod. Termed gnathobase if considered to serve in feeding (e.g., maxillules, occasionally also maxillae and thoracopods). [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Inwardly (medially) directed lobe of proximal part of appendage, e.g., of maxillules and represents main five-segmented branch of thoracopod (maxillipeds and pereopods). [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Inwardly (medially) directed lobe of mouthpart (i.e., maxillule, maxilla). Basis of maxilliped also bears endite. (simple, deeply cleft). [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Inwardly (medially) directed lobe of protopod, typically on maxillules, maxillae, and maxillipeds. (bilobed, entire).
See: Exite [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Inwardly (medially) directed lobe of proximal part of posterior mouthparts (e.g., maxillules, maxillipeds). First (proximal) endite may be termed inner plate, second termed outer plate. Shape, degree of development, and armature are of taxonomic importance, (equal, subequal, rudimentary, absent; with spines/setae). [Stachowitsch, 1992]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) A lobe on the inner (medial) margin of the protopod of an arthropod limb; enlarged anteriorly directed lobe of the basis of an isopod maxilliped. [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Inwardly (medially) directed lobe of proximal pan of posterior mouthparts (maxillules, rnaiilk. maxillipeds). If endites of first two pairs of mouthparts are paired, one may distinguish a proximal = inner and a distal = outer endite/plate/lobe. (immovable, movably articulated; rounded, cleft). [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Medially directed lobe of coxa or basis of an appendage, especially the maxilliped. [Kensley and Schotte, 1989]
(Taxon-specific: Order Mysida) Inwardly (medially) directed lobe of inner branch of biramous appendage. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Inwardly (medially) directed lobe of first two segments of maxillules and maxillae. (bilobed, with terminal tooth). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Inwardly (medially) directed lobe of proximal part (protopod) of appendage, e.g., of maxillules or maxillae. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) A non-articulating, ventral attenuation of a protopodal segment. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) An inner lobe or process on a protopodal segment of an appendage. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) Inwardly (medially) directed lobe of proximal part (protopod) of maxillule. Used to clean filtering apparatus in suspension-feeding copepod. (See also exite). [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Inwardly (medially) directed lobe of protopod of maxillule, maxilla, and maxilliped. (See also gnathobase). [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Inwardly (medially) directed lobe of protopod, typically in maxillule, maxilla, and thoracopod. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Medial extension (tooth, lobe, masticatory process) of protopod, generally used in feeding.
See: Masticatory process [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Superorder Syncarida) One of two inwardly (medially) directed lobes of maxillule or two to four lobes of maxilla. Also refers to two lobes of first segment (coxa) of maxilliped. (See also gnathobase). [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Inwardly (medially) directed lobe of proximal section (protopod) of mouthpart (i.e., maxillule, maxilla, maxilliped). [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) One of two inwardly (medially) directed, setose lobes of base (protopod) of maxillules and maxillae. (simple, bilobed, trilobed). [Stachowitsch, 1992]

Endognath

Endopod (inner and principal branch) of maxilliped. [Moore and McCormick, 1969]
Endopod of maxilliped. [McLaughlin, 1980]
Inner or principal branch of a maxilliped. [Williams, 1984]
(Taxon-specific: Order Decapoda) Inner or principal branch (endopod) of maxilliped.
See: Exognath [Stachowitsch, 1992]

Endoparasite

An internal parasite. [Butler, T. H.]

Endophragm

Septum formed by cephalic and thoracic apodemes.
(syn. arthrophragm) [McLaughlin, 1980]
Wall formed by union of apposed apodemes forming part of endoskeleton of some decapods.
(syn. arthrophragm) [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) In cephalothorax, septum of endoskeleton formed at border of each somite by inward projections (endopleurites, endosternites) of exoskeleton.
(syn. arthrophragm) [Stachowitsch, 1992]

Endophragmal skeleton

An internal skeleton composed of arthrophragms arising from. [Martin, 2005]
Complex internal skeletal structure formed by fusion of apodemes in decapods providing framework for muscle attachment, generally not strongly calcified. [Moore and McCormick, 1969]
Complex internal structure formed by fusion of apodemes, providing framework for muscle attachment. [McLaughlin, 1980]
the sternites and supporting the muscles of the leg bases (Fig. 7B). [Warner, 1977]
(Taxon-specific: Order Decapoda) Endoskeleton. [Stachowitsch, 1992]

Endopleurite

Lateral apodeme of endoskeleton in decapods. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) In endoskeleton, one in a series of rigid structures projecting into body from lateral part (pleurite, epimeral fold) of exoskeleton. Serves also as site of muscle attachment (apodeme) and may be branched.
See: Endosternite [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Lateral apodeme of endoskeleton. [McLaughlin, 1980]

Endopod

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
Inner branch of biramous appendage, especially one arising from protopodite of pleopod. [Butler, T. H.]
Inner of two branches of biramous limb, comprising ischium through to dactylus; in many the dominant or only branch.
(syn. endopodite) [Poore, 2004]
Inner ramus of biramous appendage. [McLaughlin, 1980]
Innermost ramus of limb arising from protopod basis; in the Eumalacostraca typically composed of five segments (ischium, merus, carpus, propodus, dactylus). [Moore and McCormick, 1969]
Medial of two rami arising from the protopod and constituting the biramous limb. [Brusca and Brusca, 2002]
Mesial ramus of a biramus appendage, especially one arising from the basis or from the protopodite of the pleopod. [Perez Farfante and Kensley, 1997]
Mesial ramus of biramus appendage, originating on basal segment (basis) (see Fig. 13). [Hobbs and Jass, 1988]
The inner branch of a biramous appendage. [Ingle, 1983]
The inner of the two branches of the primitive appendage (Fig. 2). [Warner, 1977]
The medial or interior ramus of a crustacean appendage. In the Isopoda, another name for a thoracic appendage (exclusive of the coxa and basis), although more typically applied to the inner ramus of a pleopod or a uropod. [Wilson, 1989]
The mesial branch of a bifurcate appendage, especially one arising from the protopodite of the pleopod of shrimps. [Chace and Hobbs, 1969]
The mesial ramus if a biramus appendage, having its origin on the basis. [Hobbs, Hobbs, and Daniel 1977]
(Taxon-specific: Order Cladocera) Lobe-like inner branch (ramus) of trunk appendage; lacks articulation with protopodal part of appendage and is more or less continuous with distal endites. Forms entire distal part of limb in certain predatory water fleas.
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Inner lobe at distal end of thoracopod or abdominal appendage in certain tadpole shrimp. Most distal (sixth) endite also occasionally termed endopod.
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Unsegmented, lobe-like inner branch of trunk appendage; often termed sixth endite.
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Inner branch of thoracic appendage (thoracopod). Unsegmented, lobe-like, and bearing marginal setae. Not articulated with protopod and therefore occasionally termed sixth endite. Serves in feeding. (oval, rectangular) (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Inner branch of biramous appendage. Refers to two-segmented branch of antennae, lobate branch (in larvae only) of mandibles, annulate branch of maxillules, six-segmented branch of maxillae, and five to six-segmented branch of thoracopods. (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Inner branch (ramus) of biramous appendage. Forms palp of maxillule and represents main five-segmented branch of thoracopod (maxillipeds and pereopods).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Inner branch (ramus) of binamous appendage. Represents only branch or main, typically five-segmented branch (ischium, mercus, carpus, propodus, dactylus) of thoracopod.
(syn. endopodite)
See: Exopod [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Inner branch (ramus) of biramous appendage. Refers to three-segmented part of peduncle of antenna, palp-shaped or more elongate inner branch of mouthparts, inner branch of pleopods and uropods; considered to represent main, basically five-segmented part of pereopod. (paddle-shaped, palp-shaped, pediform).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Inner branch (ramus) of biramous appendage. Forms palp in mouthparts (mandibles, maxillules, maxillae, maxillipeds) and represents main five-segmented part of pereopods.
(syn. endopodite)
See: Exopod [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Inner (medial) ramus of an appendage. [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Inner branch (ramus) of biramous appendage.
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Inner ramus of a biramous appendage. [Kensley and Schotte, 1989]
(Taxon-specific: Order Mysida) Inner branch (ramus) of biramous appendage. Represents palp of maxillae and maxillules as well as inner branch of maxillipeds, pereopods, and pleopods. Endopod of uropod may bear statocyst.
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Inner branch (ramus) of biramous appendage. Refers to three-segmented, flagellum-bearing branch of antennae, appendix interna-bearing branch of pleopods, and one-segmented branch of uropods, while it is considered to represent outer branch of last three thoracopods. (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Inner branch (ramus) of biramous appendage. (simple, two-, three- to four-, five-segmented) (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Setose inner branch (ramus) of thoracic appendage (thoracopod). (See also exopod). [Stachowitsch, 1992]
Lepas anatifera: cirrus V; cirrus I, and extended cirral fan. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) Inner branch (ramus) of thoracic appendage (thoracopod in ascothoracican, cirrus in other cirripeds). (one- to three-jointed, multiarticulate) (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) A ventral extension of the proximodistal axis of a limb originating on the basis of the protopod and usually segmented. Dorsal setae are absent from endopodal segments except for the penultimate and the antepenultimate segments. An endopodal segment may bear more than one ventral seta. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) Inner branch (ramus) of biramous appendage. Refers to inner, main, or only branch of antenna and maxilliped, as well as to inner branch of mandible, maxillule, and pereopod. (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The inner ramus of a biramous appendage. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Mystacocarida) Inner branch of biramous appendage. Refers to four-segmented branch of antenna and mandible of three-segmented branch of maxilliped. Single branch of uniramous appendage (e.g., maxilla) may also be interpreted as representing and endopod. (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) In distally biramous crustacean limb, the medial ramus.
(syn. endopodite) [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Class Ostracoda) Inner branch (ramus) of biramous appendage. Typically forms palp-like structure in mouthparts (e.g., mandible, maxillules) or main component of thoracopods. (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Inner or more ventral branch (ramus) of biramous appendage (antennule, antenna, trunk limb).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Inner branch (ramus) of biramous appendage. Basically six-segmented in throracopods, consisting of preischium, ischium, merus, carpus, propodus and dactylus. (See also exopod, gonophysis).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Inner branch (ramus) of biramous appendage. Represents only branch (flagellum) of antenna, palp of anterior mouthparts, and larger, basically five-segmented ramus (ischium, merus, carpus, propodus, dactylus) of thoracopods. (See also exopod).
(syn. endopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Inner branch (ramus) of biramous appendage. Represents flagellum-bearing branch of antenna, palp-like branch of maxillules and maxillae, five-segmented main branch of thoracopods, and flattened inner branch of pleopods and uropods.
(syn. endopodite)
See: Exopod [Stachowitsch, 1992]

Endopodal lobe

(Taxon-specific: Subclass Copepoda) The inner lobe of the baseoendopod of the fifth leg, derived from the endopod. [Boxshall and Halsey, 2004]

Endopodite

Main branch of an appendage issuing from the basis. [Holdich and Jones, 1983]
Mesial ramus of biramous appendage. [Williams, 1984]
The inner branch of a biramous appendage. [Mauchline, 1984]

Endoskeleton

Internal hard parts of some decapods consisting mainly of endophragms. [Moore and McCormick, 1969]
(Taxon-specific: Order Anostraca) Term occasionally applied to various more rigid internal structures serving as sites of muscle attachment. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Internal skeletal structure of head and thorax (cephalothorax). When fully developed, consists of complex system of fused projections (endopleurites, endosternites).
(syn. endophrogmal skeleton, endophragmal system)
See: Exoskeleton [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) In head, weakly developed internal skeleton consisting of two endosternites. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Thin internal skeleton of body; forms complex framework supporting limbs and caudal rami. [Stachowitsch, 1992]

Endosoma

(Taxon-specific: Subclass Copepoda) That part of the body of a mesoparasite that is inside the host. [Boxshall and Halsey, 2004]

Endosternite

Mesodermal tendonous plate below anterior part of alimentary canal (e.g., Notostraca); also firm calcareous plate between nerve cord and alimentary canal in anterior part of thorax in some crabs. [Moore and McCormick, 1969]
(Taxon-specific: Order Notostraca) Mesodermal tendonous plate below anterior part of alimentary canal; also firm calcareous plate between nerve cord and alimentary canal anteriorly in thorax of some decapods. [McLaughlin, 1980]
(Taxon-specific: Order Decapoda) In endoskeleton, one in a series of rigid structures projecting into body from ventral part (sternites) of exoskeleton. Serves also as site of muscle attachment (apodeme) and may be branched. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) One head, one of two transverse skeletal elements arising from ventral surface (sternite) and forming internal skeleton (endoskeleton). Serves as site of attachment for muscles of antennae and mouthparts, one being located directly behind esophagus, the second in region of maxilla. [Stachowitsch, 1992]

Endostome

Palate-like part of buccal frame in some brachyuran decapods.
(syn. palate) [Moore and McCormick, 1969]
Part of epistome forming palate in brachyurans and usually separated from epistome proper by transverse ridge. [Williams, 1984]
Plate inside buccal cavern surrounding mouth. [Poore, 2004]
Platelike part of buccal frame in some brachyuran decapods. [McLaughlin, 1980]
The area posterior to the epistome forming the roof of the buccal cavity. [Ingle, 1983]
(Taxon-specific: Order Decapoda) In crab-like (brachyuran) decapod, posterior part of epistome; forms roof of mouth (buccal frame) and may be separated from epistome by transverse ridge.
(syn. palate) [Stachowitsch, 1992]

Entire

(Taxon-specific: Order Isopoda) Complete; usually referring to the margin of a structure that is smooth. [Kensley and Schotte, 1989]

Ephippium

A portion of the shed carapace that functions as an egg case in some cladoceran taxa. [Brusca and Brusca, 2002]
Semielliptical modification of cuticle in dorsal region of carapace valves forming encasement for eggs, capable of withstanding dessication after being shed (Cladocera).
(pl. ephippia) [McLaughlin, 1980]
Semielliptical part of dorsal region in each valve of cladoceran branchiopods altered to form encasement for eggs, shed as unit and constructed in manner that facilitates ultimate hatching after desiccation (especially characteristic of Daphniidae).
(pl. ephippia) [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) Egg case formed by walls of brood chamber. Typically separated from rest of carapace during molting. (knobby and with two eggs, reticulated and with single egg). [Stachowitsch, 1992]

Epibenthic

Living at the surface of the substratum, or on the sea bed. [Ingle, 1992]

Epibiont

An organism attached to an external surface. [Ingle, 1983]

Epibranchial

Anterior part of branchial region of decapod (brachyuran) carapace. [Moore and McCormick, 1969]
Part of porcellanid (crab) carapace situated behind orbit and above metabranchial region. Region situated between cervical groove and linea anomurica. Often a strong spine on region, referred to as epibranchial spine.
(syn. epibranchial region) [Williams, 1984]
The region on the dorsal surface of the carapace bounded by parts of the margin of the hepatic, protogastric, metagastric and metabranchial regions and part of the antero-lateral margin of the carapace. [Ingle, 1983]

Epibranchial lobe

(Taxon-specific: Order Decapoda) See: Carapace regions c [McLaughlin, 1980]

Epibranchial region

The anterior part of the branchial region on the carapace of crabs. [Chace and Hobbs, 1969]
(Taxon-specific: Order Decapoda) Branchial region. [Stachowitsch, 1992]

Epibranchial space

Part of gill chamber above (external to ) gills. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) In each branchial chamber in cephalothorax, space above (exterior to) gills, i.e., between gills and lateral wall of carapace.
See: Hypobranchial space [Stachowitsch, 1992]

Epicaridium

(Taxon-specific: Order Isopoda) First of three larval stages (epicaridium, microniscus, cryptoniscus) of certain parasitic isopods. Free-living, characterized by stout, segmented body lacking last (= seventh) pair of pereopods. Swims by means of antennae and pleopods and attaches to intermediate host. [Stachowitsch, 1992]

Epidermis

(Taxon-specific: Order Decapoda) Outer cellular layer of body wall; secretes cuticle. Formerly termed hypodermis. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Outer cellular layer of body wall; secretes cuticle. [Stachowitsch, 1992]

Epigastric area

(Taxon-specific: Order Decapoda) See: Carapace regions f [McLaughlin, 1980]

Epigastric lobes

A paired anterior boss on the gastric region of the carapace of crabs. [Chace and Hobbs, 1969]
Anterior extension of gastric region of decapod (brachyuran) carapace. [Moore and McCormick, 1969]
Anterior lobes or subregions of gastric regions. [Williams, 1984]

Epigastric region

(Taxon-specific: Order Decapoda) Gastric region. [Stachowitsch, 1992]

Epigastric spine

A median dorsal spine posterior to rostrum, on gastric region; sometimes has the appearance of a rostrum, e.g., Pasiphaeidae. [Butler, T. H.]

Epigastric tooth

Tooth of the carapace situated above the gastric region behind the first (posteriormost) rostral tooth (Fig. 2A). [Perez Farfante and Kensley, 1997]

Epigean

Living on the surface of the earth, as opposed to spelean. [Chace and Hobbs, 1969]

Epignath

See: Epipodite [Martin, 2005]

Epimeral fold

Steep fold of endopleurites connected with branchiostegite to form branchial chamber in some decapods. [McLaughlin, 1980]
Steep fold of endopleurites in some decapods connected with branchiostegite to form branchial chamber. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) Steep fold of certain lateral elements (endopleurites) of exoskeleton. Lies parallel to and attaches to side walls (branchiostegites) of carapace, thus forming branchial chamber enclosing gills. [Stachowitsch, 1992]

Epimeral line

A line on each branchiostegite running obliquely and then posteriorly, along which a split develops in the early stages of ecdysis. [Ingle, 1983]

Epimere

A lateral fold of a somite's integument dorsal to the limbs. Sometimes called the pleurite or tergal fold. [Wilson, 1989]
Each lateral part of integument of somite.
(syn. epimeron, pleurepimere, pleurite, pleuron, pleura, pleural lobe, tergal fold) [McLaughlin, 1980]
Lateral downfold of tergite.
(syn. epimeron, pleurepimere, pleurite, pleuron (pl., pleura), pleura (pl., pleurae), tergal fold) [Moore and McCormick, 1969]
Lateral part of wall of body somites situated between tergum and insertion of appendages. [Williams, 1984]
(Taxon-specific: Order Cumacea) Poorly developed lateral part/extension of somites in pereon and pleon region. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Pleurite.
(syn. epimeron) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Lateral projection of segments of anterior abdomen (pleomere). (posterodistal angle: acute, rounded, quadrate, prolonged into large tooth; margins: smooth, serrate, setose).
(syn. epimeral plate) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Lateral extension of body,either of the body wall proper or, in the pereon, more frequently of coxae of pereopods (more accurately termed coxal plate).
(syn. epimeron) [Stachowitsch, 1992]

Epimeron

See: Epimere [Martin, 2005]
Lateral projection of pereonite or pleonite. [Holdich and Jones, 1983]
See epimere. [McLaughlin, 1980]
(Taxon-specific: Order Isopoda) Lateral part of a somite. [Kensley and Schotte, 1989]

Epimorphic development

Direct development thought to result from a delay in hatching of the embryo, which causes the nauplius (and any other possible larval stages) to be suppressed or absent. [Brusca and Brusca, 2002]
In which larval stages are supressed or passed within the egg prior to hatching and the juvenile hatches with adult morphology. [Ingle, 1992]

Epipelagic

Zone usually in the ocean from surface to 200m, or referring to its inhabitants. [Butler, T. H.]

Epiphyte

A plant attached to an external surface of another plant or animal which uses its host for support. [Ingle, 1983]

Epipod

Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
A lateral extension from the base of an appendage (Fig. 2). [Warner, 1977]
A respiratory endite arising from the coxal segment of a pereiopod. [Ingle, 1983]
A small projection arising from the thoracic legs. [Mauchline, 1984]
Lateral branch of limb attached sometimes with gill (podobranch) to coxa, coxal endite.
(syn. epipodite) [Poore, 2004]
Lateral exite of the coxa of a thoracic appendage, sometimes branchial in function (Fig. 3C). [Perez Farfante and Kensley, 1997]
Laterally directed lobe (exite ) of the basal segment ( coxa ) of the maxilliped. [Wilson, 1989]
Laterally directed ramus (exite) of coxa; may be present or absent. [Moore and McCormick, 1969]
Respiratory process arising from coxa of a thoracic appendage; usually elongate and flat, but may be folded; has taxonomic value. [Butler, T. H.]
(Taxon-specific: Order Cladocera) In trunk appendage, laterally (outwardly) directed lobe projecting from base of protopod. Represents only lobe articulated with appendage and serves in respiration.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Dorsally directed lobe extending from lateral (outer) margin of thoracic appendage (thoracopod) or abdominal appendage. Serves in respiration.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) In trunk appendage, fleshy, lobe-like projection from base of protopod. Serves, along with inner wall of carapace, in respiration. Dorsally directed part of flabellum may also represent an epipod.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) In thoracic appendage (thoracopod), laterally (outwardly) directed lobe of protopod; located distal to preepipod(s). Serves in respiration.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Pseudepipod. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) In first pair of maxillipeds, enlarged lateral lobe of first segment (coxa). Consists of two parts, the first directed posteriorly into branchial chamber and bearing branchial lobules, the second (siphonal lobe) directed anteriorly to form part of siphon (the latter may alternately be interpreted as representing an exopod).
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Well-developed projection of first segment (coxa) of each maxilliped. If fully developed, consists of stalk-like proximal section (muscular peduncle) and distal expanded section. The latter may further bear small lobe basally and finger-like process (terminal spine) terminally. Projects posteriorly into branchial chamber and serves in respiration. (kidney-shaped, sickle-shaped, spoon shaped).
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) In appendage (pereopod) of pereon, inwardly directed lobe of protopod. Serves in respiration and therefore frequently termed coxal gill or branchia.
(syn. epipodite) [Stachowitsch, 1992]
Nomenclature of isopod cephalon (A). Examples of isopod mouth appendages: Idoteidae (B, C, F, H); Cirolanidae (D, E, G, I). [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) (Figure only.) [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Lateral extension of a protopodite. [Kensley and Schotte, 1989]
(Taxon-specific: Order Mysida) Dorsal projection from outer branch (exopod) of thoracopods. First thoracic epipod extends dorsally and posteriorly under carapace and serves to renew water supply for respiration. In certain mysidaceans, epipods of thoracopods 2-7 form ramified gills (branchiae).
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Laterally directed branch of base of first five thoracic appendages (thoracopods); with respiratory function in thoracopods 3-5.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) In thoracic appendage (thoracopod), laterally (outwardly) directed lobe of protopod. Serves in respiration.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Flabellum. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Extension (usually setose flat lobe) of lateral protopod; in ostracodes it often forms a branchial plate used to circulate water. [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Class Ostracoda) Laterally directed lobe of protopod. May also refer to modified exopod (branchial plate) of appendage.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) One of two projections of first segment (coxa) of thoracopod. Serves in respiration.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Projection of basal section (protopod) of each maxilliped. Extends posteriorly under carapace, serving in respiration and ventilation of brood pouch in female.
(syn. epipodite) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Laterally (outwardly) directed lobe of basal segment (coxa) of thoracic appendage (thoracopod). Those of second through eighth thoracopods serve in respiration and are therefore termed gills or podobranchs.
(syn. epipodite) [Stachowitsch, 1992]

Epipodite

A lateral plate-like extension from the coxa often bearing gill filaments. [Hobbs, Hobbs, and Daniel 1977]
Branchial exite borne by the basal region of an appendage ( especially the maxilliped). [Holdich and Jones, 1983]
Laterally directed exite of protopod, usually branchial in function. [McLaughlin, 1980]
Outgrowth of first 7 thoracic coxae. [Williams, 1984]
(Taxon-specific: Order Decapoda) Inwardly (medially) directed lobe of first two segments of thoracopods (maxillipeds and pereopods). Typically with respiratory function. (simple, lobate).
(syn. epipod)
See: Mastigobranch [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) An outer lobe (exite) on the outer margin of a protopodal segment (coxa) of an appendage. [Boxshall and Halsey, 2004]

Episternum

Posterolateral projection of various sterna of decapods. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) On ventral surface of cephalothorax, one in a series of posterolateral projections of successive sternites; serves as ventral support for articulation of pereopod. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Posterolateral projection of various sterna. [McLaughlin, 1980]

Epistome

A broad strongly calcified plate in front of, and above, the mouth. It represents the fused sternites of the third and fourth segments. [Warner, 1977]
A transverse plate situated anterior to the mouth. [Hobbs, Hobbs, and Daniel 1977]
Antennal sternum mainly represented by epistome, a plate of varying shape lying between labrum and bases of antennae. In shrimps, comparatively narrow and separated on each side from lateral portions of carapace by exhalant branchial channels. In Astacidea and Anomura, broad and in contact with carapace on each side; in Brachyura, becoming firmly united with carapace. The epistome forms the anterior part of the buccal frame. [Williams, 1984]
Front part of head above labrum, sometimes produced anteriorly into a spine. [Holdich and Jones, 1983]
Plate of varying shape between labrum and bases of antennae in brachyuran decapods, also defined as sternum of antennal somite. [Moore and McCormick, 1969]
Plate of varying shape between labrum and bases of antennae; also sternum of antennal somite. [McLaughlin, 1980]
Region of carapace between front of carapace, antennules and buccal region. [Poore, 2004]
The transverse plate anterior to the mouth area in crayfishes and crabs. [Chace and Hobbs, 1969]
The transverse plate forming the anterior border of the buccal frame, laterally fused with the carapace and (usually), anteriorly fused with the front. [Ingle, 1983]
Transverse plate (usually somewhat triangular in shape) situated ventrally and anterior to gnathal appendages of crayfishes (see Fig. 23i). [Hobbs and Jass, 1988]
Transverse plate anterior to mouth area. [Perez Farfante and Kensley, 1997]
(Taxon-specific: Order Diplostraca) Rostrum. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) On underside of head, pair of small plates between bases of antennules. Adjoined posteriorly by upper lip (labrum). [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Relatively large, plate-like structure in front of mouth on underside of head. May be divided into more narrow anterior part extending between antennae and broader posterior portion (endostome). Adjoined posteriorly by labrum. Also considered to be sternum of second cephalic segment (antennal somite).
See: Metapon [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) On underside of head, plate-like structure in front of upper lip (labrum). (pointed, rounded). [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Relatively large, plate-like structure in front of mouth on underside of head (cephalon); adjoined posteriorly by labrum. [Stachowitsch, 1992]

Epizoism

An association in which animals live on others for substrate requirements. [Ingle, 1983]

Erichthus larva

(Taxon-specific: Order Stomatopoda) Later larval stage of most stomatopods; similar stage in other stomatopods is termed alima. [Stachowitsch, 1992]

Esophageal connective

(Taxon-specific: Order Cladocera) One of two strands of nerve tissue surrounding esophagus and connecting posterior part of brain with ventral nerve cord. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) One of two strands of nerve tissue extending around esophagus and connecting posterior part of supraesophageal ganglion with antennal ganglion (tritocerebrum). [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) One of two strands of nerve tissue surrounding esophagus and connecting supraesophageal ganglion with subesophageal mass. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Circumesophageal connective. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) One of two strands of nerve tissue surrounding esophagus and connecting brain (supraesophageal ganglion) with subesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) One of two strands o( nerve tissue surrounding foregut and connecting brain (supraesophageal ganglion) with subesophageal ganglion. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) One of two strands of nerve tissue surrounding esophagus and joining supraesophageal ganglion to subesophageal ganglion or directly to ventral nerve cord. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Circumoral connective. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) One of two strands of nerve tissue surrounding esophagus and connecting brain (supraesophageal ganglion) with ventral nerve cord. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) One of two strands of nerve tissue extending around esophagus and connecting supraesophageal and subesophageal ganglia.
(syn. circumesophageal connective) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Circumesophageal connective. [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) One of two strands of nerve tissue extending from posterior part of brain (tritocerebrum) around esophagus. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) One of two strands of nerve tissue surrounding esophagus and connecting supraesophageal ganglion to ventral nerve cord. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) One of two strands of nerve tissue surrounding esophagus and connecting brain (supraesophageal ganglion) with ventral nerve cord. [Stachowitsch, 1992]

Esophagus

Anterior part of alimentary canal between pharynx or mouth and stomach or stomodeum.
(syn. oesophagus) [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) Relatively short and narrow anterior section of digestive tract. From mouth, esophagus curves forward, then upward and backward to more expanded midgut. May be highly elongated in certain predatory water fleas. [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Relatively short, narrow section of digestive tract between mouth and midgut. Directed dorsally, then posteriorly. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Relatively short and narrow anterior section of digestive tract. From mouth, esophagus curves forward, then upward and backward to more expanded midgut. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Relatively short section of digestive tract between mouth and midgut. Directed dorsally, then posteriorly. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Anterior section of digestive tract. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Short, relatively narrow section of digestive tract between mouth and stomach.
(syn. oesophagus) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Relatively short section of digestive tract between mouth and stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Relatively short, narrow, cuticle-lined section of digestive tract between mouth and cardiac stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Relatively short, cuticle-lined section of digestive tract between mouth and stomach. Esophagus and stomach together form foregut. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Foregut. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Relatively short section of digestive tract between mouth and stomach. May be lined internally with posteriorly directed spines. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Short, cuticle-lined section of digestive tract between mouth and stomach. Esophagus and stomach form foregut. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Section of digestive tract between mouth and midgut; partially contained within proboscis. (See also foregut). [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Muscular, cuticle-lined, and relatively narrow section of digestive tract between mouth and midgut. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Narrow section fo digestive tract between mouth and stomach; cuticle-lined, muscular, and basically corresponding to foregut. [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Anterior section of foregut (stomodeum). From mouth, esophagus curves forward, then upward and backward. Surrounded laterally by posterior part of brain (tritocerebrum and esophageal connectives). May refer to entire foregut. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Narrow, muscular section of digestive tract between mouth and midgut. Cuticle-lined and occasionally armed with ridges or modified into gastric mill. (See also foregut). [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) In anaspidacean, relatively short, narrow section of digestive tract between mouth and stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Relatively short, slender section of digestive tract between mouth and stomach. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Short section of digestive tract between mouth and stomach. [Stachowitsch, 1992]

Esthetasc

Aesthetasc. [Stachowitsch, 1992]
See aesthetasc. [McLaughlin, 1980]
Sensory seta covered by delicate cuticle projecting from most antennules and antennae.
(syn. olfactory hair, esthete) [Moore and McCormick, 1969]

Excavate

(Taxon-specific: Order Isopoda) Hollowed out. [Kensley and Schotte, 1989]

Excretory duct

(Taxon-specific: Order Decapoda) In antennal gland, short duct leading from bladder to excretory pore on basal segment (coxa) of antenna.
See: Excretory tubule [Stachowitsch, 1992]

Excretory organ

(Taxon-specific: Order Decapoda) Antennal gland. [Stachowitsch, 1992]

Excretory pore

An opening, on the first penduncular segment of the antenna, of the excretory organ or green gland. [Ingle, 1983]
(Taxon-specific: Order Decapoda) Opening of each antennal gland to exterior; located on basal segment (coxa) of antenna. May bear operculum.
(syn. nephropore) [Stachowitsch, 1992]

Excretory tubule

(Taxon-specific: Order Decapoda) Narrow section of antennal gland occasionally joining second part of end sac (labyrinth) to bladder.
See: Excretory duct [Stachowitsch, 1992]

Exhalant passage

Anterior to gill chamber leading to large anterior opening, with scaphognathite for driving water outward. [McLaughlin, 1980]
Canal in front of gill chamber containing scaphognathite which functions for driving water outward, leads to large anterior opening. [Moore and McCormick, 1969]
(Taxon-specific: Order Decapoda) On each side of cephalothorax, narrow chamber or canal leading from branchial chamber to exterior at anterior end. Water current driven by scaphognathite. [Stachowitsch, 1992]

Exite

Lateral outgrowth of the protopod. [Brusca and Brusca, 2002]
Laterally directed lobe arising from external margin of protopodal segment. [McLaughlin, 1980]
Laterally directed ramus of protopodal segment of limb (e.g., Notostraca). [Moore and McCormick, 1969]
Outwardly directed projection arising from the basal region of an appendage. [Holdich and Jones, 1983]
(Taxon-specific: Order Decapoda) Outwardly (laterally) directed, lobe-like branch of protopod. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Outwardly (laterally) directed lobe of basal part of maxilla. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Outwardly (laterally) directed branch of proximal part (protopod) of appendage, e.g., of maxillae. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) A non-articulating, dorsal attenuation of a protopodal segment. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) Any outer lobe on a protopodal segment of an appendage. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Copepoda) Outwardly (laterally) directed lobe of proximal part (protopod) of maxillule. (See also endite). [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Term applied to small lobe of maxillule in anaspidacean. Also variously interpreted as representing an endopod or exopod. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) In maxillule, outwardly (laterally) directed, setose, lobe-like branch of base (protopod). (plate-like, rudimentary, absent).
See: Endite [Stachowitsch, 1992]

Exognath

Exopod (outer and secondary branch) of maxilliped. [Moore and McCormick, 1969]
Exopod of maxilliped. [McLaughlin, 1980]
Lateral or secondary branch of maxilliped. [Williams, 1984]
(Taxon-specific: Order Decapoda) Outer branch (exopod) of maxilliped.
See: Endognath [Stachowitsch, 1992]

Exopod

See: Exopodite [Martin, 2005]
Schematic drawing of a thoracic leg. [Holthuis, 1993]
(Figure only.) [Holthuis, 1993]
Lateral of two rami arising from the protopod and constituting the biramous limb. [Brusca and Brusca, 2002]
Lateral ramus of a biramus appendage, arising from the basis, or from the protopodite (Fig. 3C). [Perez Farfante and Kensley, 1997]
Lateral ramus of biramus appendage, originating on second segment (basis) from base (see Fig. 13). [Hobbs and Jass, 1988]
Outer branch of a biramous appendage. [Ingle, 1980]
Outer of two branches of biramous limb, comprising one or several short articles arising from basis; absent from many limbs.
(syn. exopodite) [Poore, 2004]
Outer ramus of limb arising from protopod basis; may contain variable number of segments or be much reduced or lacking. [Moore and McCormick, 1969]
The lateral branch of a bifurcate appendage arising from the basis or from the protopodite. [Chace and Hobbs, 1969]
The lateral or exterior ramus of a crustacean basis. In the Isopoda, applied to the outer ramus of a pleopod or uropod. [Wilson, 1989]
The lateral ramus of a biramous appendage, having its origin on the basis. [Hobbs, Hobbs, and Daniel 1977]
The outer of two branches of the primitive appendage (Fig. 2). [Warner, 1977]
(Taxon-specific: Order Cladocera) Lobe-like outer branch (ramus) of trunk appendage; lacks articulation with protopodal part of appendage. Reduced in certain predatory water fleas.
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Large, setose outer lobe of thoracic appendage (thoracopod) ot abdominal appendage. Extends dorsally and ventrally from narrow point of attachment; modified on last (11th) thoracopods in female to form ovisac.
(syn. exopodite, flabellum) [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Outer branch of trunk appendage; unsegmented, prolonged dorsally and ventrally, and bearing marginal setae. Dorsal extension occasionally interpreted as representing additional epipod or flabellum, ventral extension as exopod proper.
(syn. exopodite, flabellum) [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Outer branch of thoracic appendage (thoracopod). Unsegmented, lobe-like, and bearing marginal setae; articulated with protopod. Serves in locomotion. (See also endopod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Outer branch of biramous appendage. Refers to annulate outer branch of antennae, six-segmented branch (in larvae only) of mandibles, one-segmented branch of maxillules, as well as two-segmented branches of maxillae and thoracopods. (See also endopod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Outer branch (ramus) of biramous appendage. Represents small branch of pereopods; occasionally interpreted as representing flabellum of maxilla as well as siphonal lobe of of first maxillipeds.
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Outer branch (ramus) of biramous appendage. May be present as small ramus on chelipeds and anterior pereopods. Scale-like projection (antennal scale) on antenna considered to represent exopod.
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Outer branch (ramus) of biramous appendage (endopod, exopod). Refers to antennal scale (scaphocerite) of antenna, scaphognathite of maxillula, flagelliform branch of maxillipeds, and variously developed outer branch of pereopods, pleo-pods, and uropods. (annulate, flagelliform, scale-like, spine-like).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Outer branch (ramus) of biramous appendage (e.g., pleopod, uropod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Outer (lateral) ramus of an appendage. [Wetzer et al. 1997]
(Taxon-specific: Order Isopoda) Outer branch (ramus) of biramous appendage (e.g., pleopod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Outer ramus of a paired appendage. [Kensley and Schotte, 1989]
(Taxon-specific: Order Mysida) Outer branch (ramus) of biramous appendage. Represents scale-like structure (antennal scale) of antenna and flagellum-shaped branch of maxilipeds, thoracopods, and pleopods. (annulate, elongate, flattened; natatory; reduced).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Outer branch (ramus) of biramous appendage. Refers to two-segmented branch of antennae, one-segmented, gill-bearing branch of pleopods, and two-segmented branch of uropods, while it is considered to represent inner branch of last three thoracopods. (See also endopod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Outer branch (ramus) of biramous appendage. (elongate and slender, flattened = lamellar = scale-like = plate-like).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Setose outer branch (ramus) of thoracic appendage (thoracopod). Exopod of first two thoracopods may bear medially directed flabellum. (See also endopod). [Stachowitsch, 1992]
Lepas anatifera: cirrus V; cirrus I, and extended cirral fan. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) Outer branch (ramus) of thoracic appendage (thoracopod in ascothoracican, cirrus in other cirripeds). (one- to three-jointed, multiarticulate) (See also endopod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) A dorsal extension of the proximodistal axis of a limb originating on the basis of the protopod and usually segmented. Segments of the exopod bear a dorsal seta and often a ventral seta, but usually there is only one of each kind of seta on a segment. [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Copepoda) Outer branch (ramus) of biramous appendage. Refers to outer branch of antenna (occasionally reduced), mandible, maxillule, and pereopod. (See also endopod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The outer ramus of a biramous appendage. [Boxshall and Halsey, 2004]
(Taxon-specific: Subclass Mystacocarida) Out branch of biramous appendage. Refers to nine-segmented branch of antenna, seven-segmented branch of mandible, and one-segmented branch of maxilliped. (See also endopod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) In distally biramous crustacean limb, the lateral ramus.
(syn. exopodite) [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Class Ostracoda) Outer branch (ramus) of biramous appendage. Often developed as a branchial plate. (See also endopod).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Outer or more dorsal branch (ramus) of biramous appendage (antennule, antenna, trunk limb).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Outer branch (ramus) of biramous appendage. In anaspidacean, representing scale-like branch (scaphocerite) of antenna (also occasionally in bathynellacean) and annulated ramus of thoracopods. (annulate, scale-shaped, spatulate, styliform).
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Outer branch (ramus) of biramous appendage. Present as small lobe on maxillae, palp-like structure of maxilliped, smaller, one- to two-segmented ramus of thoracopods, and two-segmented remud of uropod.
(syn. exopodite) [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Outer branch (ramus) of biramous appendage. Represents scale (scaphocerite) of antenna, one-segmented lobe of maxilla in certain euphausiaceans, relatively small, two-segmented outer branch of thoracopods, and flattened outer branch of pleopods and uropods.
(syn. exopodite)
See: Endopod [Stachowitsch, 1992]

Exopodite

Lateral branch of the basis. [Holdich and Jones, 1983]
Lateral ramus of biramous appendage. [Williams, 1984]
Outer ramus of biramous appendage. [McLaughlin, 1980]
The outer branch of a biramous appendage. [Mauchline, 1984]
The outer of the two branches of the primitive appendage. [Warner, 1977]

Exorbital process

A process arising from the outer orbital margin. [Ingle, 1980]
(Taxon-specific: Order Decapoda) On carapace of crab-like (brachyuran) decapod, tooth-like projection on margin of orbit.
(syn. external orbital tooth) [Stachowitsch, 1992]

Exoskeleton

Chitinous or calcified outer integument of crustaceans. [McLaughlin, 1980]
Chitinous or calcined outer integument of body (pleurites, sternites, tergites) and appendages.
See: Endoskeleton [Stachowitsch, 1992]
Entire horny (in part chitinous) more or less calcified outer covering of crustacean body and its appendages. [Moore and McCormick, 1969]
Outer covering of arthropods; "shell". [Hobbs and Jass, 1988]
The skeleton covering the outside of the body. [Ingle, 1983]

Explosive cells

Wandering blood cells that release a clotting agent at sites of injury or autotomy. [Brusca and Brusca, 2002]

Extended development

A long, regularly ocurring moulting sequence within a species producing morphologically discrete stages at each ecdysis, each showing some advancement over the previous stage. [Ingle, 1992]

Extensor margin

Endopod of Mxp 3, lateral; and endopod of Mxp 3, including basal 2 articles, distal articles omitted, central. Based on Munidopsis. [Baba, 2005]
(Figure only.) [Baba, 2005]
Outer or longer margin of a flexed appendage. [Butler, T. H.]
The outer or longer margin of a flexed appendage. [Chace and Hobbs, 1969]

Extensor muscle

The muscle which extends the leg at the MC joint (Fig. 19). [Warner, 1977]

Extensor surface

The unopposed surface of a flexed podomere of an appendage. [Hobbs, Hobbs, and Daniel 1977]
Unopposed surface (face) of flexible podomere of an appendage (in opposition to opposed, flexor surface). [Hobbs and Jass, 1988]

Externa

reproductive part of a rhizocephalan parasite positioned outside the host's body. [Brusca and Brusca, 2002]
(Taxon-specific: Subclass Cirripedia) Brood chamber.
(syn. reproductive sac) [Stachowitsch, 1992]

Eye

(Taxon-specific: Order Cumacea) Photosensitive organ on dorsal surface of carapace; typically unpaired and positioned on ocular lobe (paired, unpaired). [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) One of two photosensitive organs on carapace; positioned anterolaterally on short projections (ocular lobes). [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) One of two organs of vision, each consisting of numerous ommatidia covered by cornea; typically positioned at tip of eyestalk. (sessile, stalked; club-shaped, reniform, spherical). [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) One of two unstalked (sessile) organs of vision on each side of head. (contiguous, convex = globular, immense, oval, reniform; blind, oculate).
(syn. compound eye) [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Organ of vision on cephalon; when present, usually small and sessile, (sessile, stalked; pear-shaped, reniform, oval, contiguous).
(syn. compound eye) [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) One of two organs of vision, each located distally on ocular peduncle. (divided, undivided, fused; plate-like, pyriform).
(syn. compound eye) [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Large, paired organ of vision on head (cephalon); each eye is positioned on eyestalk (ocular peduncle) originating on acron. (See also cornea, nauplius eye).
(syn. compound eye) [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) One of two organs of vision located at tip of eyestalk (ocular peduncle).
(syn. compound eye) [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Compund eye, nauplius eye. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Compound eye, nauplius eye. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) If present (anaspidacean), one of two organs of vision. (sessile, stalked; anteriorly/laterally directed). [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Compound eye, nauplius eye. [Stachowitsch, 1992]

Eye tubercle

(Taxon-specific: Order Notostraca) Slight elevation of carapace covering compound eye. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Protuberance on anterodorsal region of each valve; overlies ocular sinus and serves as lens for compound eye. (biconvex, concavo-convex, conical, hemispherical, tubular). [Stachowitsch, 1992]

Eyes

Compound structures borne on a small anteriorly directed lobes of the carapace. [Holdich and Jones, 1983]
Visual organ, in Crustacean either compound or naupliar (simple). [Moore and McCormick, 1969]
(Taxon-specific: Order Cladocera) Compound eye, nauplius eye. [Stachowitsch, 1992]
(Taxon-specific: Order Notostraca) Compound eye, nauplius eye. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Compound eye, nauplius eye. [Stachowitsch, 1992]
(Taxon-specific: Order Anostraca) Compound eye, nauplius eye. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) One of two sensory organs associated with anterior end of labrum on underside of head (cephalon). Located under surface of cuticle and connected to brain by optic nerve.
(syn. compound eye) [Stachowitsch, 1992]
(Taxon-specific: Subclass Mystacocarida) Ocellus. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Compound eye, nauplius eye. [Stachowitsch, 1992]

Eyespine

Anterior part of carapace, including ocular peduncles, based on Munidopsis. [Baba, 2005]
(Figure only.) [Baba, 2005]

Eyestalk

A pre-segmental appendage on either side of the median line of the carapace and bearing on its distal surface the cornea. [Ingle, 1983]
Articulating eye comprising peduncle and (usually) pigmented cornea. [Poore, 2004]
Peduncle movably articulated with head, carrying eye at its distal extremity, may be divided into 2 or 3 segments and may be retractable.
(syn. ocular peduncle) [Moore and McCormick, 1969]
Peduncle or unfaceted part of the eye supporting the cornea. [Perez Farfante and Kensley, 1997]
Peduncle or unfaceted protion of eye bearing cornea. [Butler, T. H.]
See ocular peduncle. [McLaughlin, 1980]
The peduncle or unfaceted portion of the eye supporting the cornea. [Chace and Hobbs, 1969]
(Taxon-specific: Order Decapoda) Ocular peduncle. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Ocular peduncle. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Ocular peduncle. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) In anaspidacean, one of two projections of head bearing eyes; may bear tubercle. [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Ocular peduncle. [Stachowitsch, 1992]

Falcate

Sickle-shaped or hooked. [McLaughlin, 1980]
(Taxon-specific: Order Isopoda) Sickle shaped; curved and tapering to a point. [Kensley and Schotte, 1989]
(Taxon-specific: Subclass Copepoda) Used for a curved or hooked element. [Boxshall and Halsey, 2004]

Family

A major subdivision of an order, suborder or infraorder in the classification of animals, usually consisting of several genera. [Bliss, 1982]

Fan seta

A specialized seta on the distal tip of the maxilliped's endite. It is made thin, hyaline cuticle (difficult to see) and is usually broad with many laterally pointed lobes. In the munnopsids, it appears at two distinct types: a medial, more heavily sclerotized seta with fewer lobes, generally found on the distomedial corner of the maxillipedal endite; and a thin lamellar form placed in a row just proximal to the distal edge of the endite. [Wilson, 1989]

Fastigial plate

(Taxon-specific: Order Stomatopoda) Anteriormost of three plates (fastigial, ocular, postocular) composing acron at tip of head. [Stachowitsch, 1992]

Fecundity

Relative number of eggs, sperm, or young produced by a shrimp. [Butler, T. H.]

Fenestra

(Taxon-specific: Class Ostracoda) Type of valve sculpture: one in a series openings either in ridge (carina) or wall (murus) of reticulate pattern. [Stachowitsch, 1992]

Fertilization duct

(Taxon-specific: Subclass Copepoda) In female reproductive system, narrow duct connecting median seminal receptacle to end of each oviduct. [Stachowitsch, 1992]

Fifth limb

(Taxon-specific: Class Ostracoda) 5th limb, labeled "maxilla" in many papers; controversially considered to be and labeled "1st trunk leg," "1st thoracic limb" or "maxilliped" by some podocopid specialists; use care in reading literature descriptions.
(syn. 2nd maxilla) [Cohen, Peterson, and Maddocks, in press]

Filament

(Taxon-specific: Order Diplostraca) Slender, basally forked projection on dorsal surface of telson. Relative position within series of spines on telson is of taxonomic importance.
(syn. forked filament) [Stachowitsch, 1992]

Filamentary appendage

Membranous process developed on body in many cirripeds (Ascothoracica, Lepadomorpha) commonly on bases of cirri; may contain branches of testes; presumed to be respiratory in function. [Moore and McCormick, 1969]
Membranous process developed on body in some cirripeds commonly at base of cirrus. [McLaughlin, 1980]
Lepas anatifera: left valve removed. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]
Lepas anatifera: cirrus V; cirrus I, and extended cirral fan. [Anderson, 1980]
(Taxon-specific: Subclass Cirripedia) (Figure only.) [Anderson, 1980]

Filter chamber

Space beneath thorax (e.g., phyllocarids) enclosed by ventral body wall and rhythmically moved thoracopods which functions for food-gathering from currents sucked into it. [Moore and McCormick, 1969]
Space beneath thorax enclosed by ventral body wall and moving thoracopods used for food-gathering. [McLaughlin, 1980]

Filtering apparatus

(Taxon-specific: Order Stomatopoda) Series of plates (median, upper lateral, lower lateral) separating larger anterior division of stomach (cardiac stomach) from smaller posterior division (pyloric stomach). Functions as sieve.
(syn. posterior cardiac plate) [Stachowitsch, 1992]

Finger

One of terminal elements of chela; movable finger is the dactylus; fixed finger is the terminal extension of propodus. [Butler, T. H.]
One of the rami of the chela; the movable finger consisting of the dactyl and the immovable finger of the opposable part of the propodus. [Hobbs, Hobbs, and Daniel 1977]
One of the terminal elements forming the pincers of a chela, the movable finger being the dactyl and the immovable finger the terminal extension of the propodus. [Chace and Hobbs, 1969]
One of two rami of chela; movable finger (dactyl) and immovabe finger of opposable part of propodus. [Hobbs and Jass, 1988]
(Taxon-specific: Order Tanaidacea) Chela. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) One of two finger-like elements of chela. One may distinguish a movable finger (dactyl) bearing down on a fixed finger (thumb, pollex), which is an extension of expanded propodus (manus, palm). (straight, curved, agape, closely fitting; cutting edge: corneous, entire, pectinate, serrate, sharp, sinuous, tuberculate, toothed; tips: acute, bidentate, corneous, incurved, spoon-shaped, subacute). [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Dactyl. [Stachowitsch, 1992]

Fingers

Narrow scissor-like blades of pincer end of cheliped, movable finger being dactyl, and fixed finger the terminal part of propodus.
(syn. digits) [Williams, 1984]
Scissor-like blades of claw end of cheliped, one finger movable and other immovable (fixed); very exceptionally (Psalidopus) both fingers are movable. [Moore and McCormick, 1969]

Finishing arthrodial membrane

(Taxon-specific: Subclass Copepoda) An arthrodial membrane which completes a segment and whose formation defines the location of the segment along the proximodistal axis of a limb. The finishing arthrodial membrane usually is the distal arthrodial membrane of a segment that forms proximal to the source segment, and is the proximal arthrodial membrane of a segment that forms distal to the source segment. [Ferrari and Dahms, in press]

First antenna

See: Antennule [Martin, 2005]
See antennule. [McLaughlin, 1980]
(Taxon-specific: Order Cumacea) Antennule. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Antennule. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Antennule. [Stachowitsch, 1992]
(Taxon-specific: Order Mysida) Antennule. [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Antennule. [Stachowitsch, 1992]
(Taxon-specific: Subclass Cirripedia) Antennule. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Antennule. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) 1st (cephalic) pair of limbs.
(syn. antennula) [Cohen, Peterson, and Maddocks, in press]
(Taxon-specific: Class Ostracoda) Antennule. [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Antennule. [Stachowitsch, 1992]

First form male

Sexually functional male crayfish (Cambaridae)); at least one terminal element of first pleopod usually corneouss. [Hobbs and Jass, 1988]
The breeding form of male crayfishes in which one of the terminal projections of the first pleopod is corneous, as opposed to the second from male in which this projection is not corneous. [Chace and Hobbs, 1969]
The sexually functional male cambarid, most readily recognized by the possession of at least one corneous terminal element on the first pleopod. [Hobbs, Hobbs, and Daniel 1977]

First maxilla

See: Maxillule [Martin, 2005]
See maxillule. [McLaughlin, 1980]
(Taxon-specific: Order Anostraca) Maxillule. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Maxillule. [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Maxillule. [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Maxillule. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Maxillule. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) The paired limb of the somite of the cephalon posterior to the mandible.
(syn. maxilla 1) [Ferrari and Dahms, in press]
(Taxon-specific: Subclass Mystacocarida) Maxillule. [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Maxillule. [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Maxillule. [Stachowitsch, 1992]

First-stage lobster

The first of three free-swimming larval stages of a true lobster; corresponds to the mysis stage of a penaeid shrimp. [Bliss, 1982]

Fissure

Separation of shell by sulcus; occurs on carapace between antennal and postorbital spines of some crangonid shrimps. [Butler, T. H.]

Fixed finger

Entire animal, right appendages omitted, dorsal view, based on Munida. [Baba, 2005]
(Figure only.) [Baba, 2005]
Immovable distal part of propodus of chela.
(syn. pollex, thumb) [Moore and McCormick, 1969]
Immovable distal part of propodus of chela.
(syn. pollex) [McLaughlin, 1980]
Prolongation of propodus of chelate limb.
(syn. pollex) [Poore, 2004]
see Finger. [Butler, T. H.]
(Taxon-specific: Order Decapoda) Finger.
(syn. immovable finger, pollex, thumb) [Stachowitsch, 1992]

Flabellum

Thin distal exite of branchiopod gnathobase with setose margin. [Moore and McCormick, 1969]
(Taxon-specific: Class Branchiopoda) Thin distal exite; or epipodite of thoracopod. [McLaughlin, 1980]
(Taxon-specific: Order Notostraca) Exopod. [Stachowitsch, 1992]
(Taxon-specific: Order Diplostraca) Term applied to entire outer branch (exopod) of trunk appendage or to dorsally directed part of exopod only. Modified in 9th through 11th appendages into elongate, slender structures for attachment of eggs. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Flattened lateral branch of maxilla. Considered to represent an exopod. [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) On first two pairs of thoracic appendages (thoracopods), medially (backwardly) directed projection from base of outer branch (exopod).
(syn. epipod) [Stachowitsch, 1992]

Flagellar lobule

A slender process extending from the distomesial angle of that lateral major lobe of the first maxilliped. [Hobbs, Hobbs, and Daniel 1977]

Flagellomere

(Taxon-specific: Subclass Copepoda) A segment of a flagellum which is part of the ramus of antenna 1 or antenna 2 of many crustaceans. Flagellomeres are not moved by muscles and are formed distad to the first flagellomere, which is the source segment for the flagellomeres. Copepods do not have a flagellum on either antenna 1 or antenna 2. [Ferrari and Dahms, in press]

Flagellum

A long, multi-segmented sensory appendage found at the distal ends of the antennae. [Mauchline, 1984]
Antennal endopodite; thin, tapering, multiarticulate, elongate extension of antenna and antennule (distal to peduncle). [Hobbs and Jass, 1988]
Multiarticulate appendage of antennule (2 present) and antenna (1 only); also appendage of exopods of maxillipeds.
(pl. flagella) [Poore, 2004]
Multiarticulate distal portion of antennule, antenna, or exopod.
(pl. flagella) [McLaughlin, 1980]
Multiarticulate, usually whiplike terminal part of the antennule or antenna (Fig. 3B).
(pl. flagella) [Perez Farfante and Kensley, 1997]
Slender, multiarticulate distal part of antennule, antenna or exopod. [Moore and McCormick, 1969]
The distal, multiarticulate endite attached to the antennal and antennular peduncle and exopods of the maxillipeds. [Ingle, 1983]
The long, tapering distal part of either the antennula or antenna, generally made of many annuli. [Wilson, 1989]
The multiarticulate, typically filamentous part of an antennule or antenna. [Hobbs, Hobbs, and Daniel 1977]
The multiarticulate, usually whiplike terminal portion of an antennule or antenna.
(pl. flagella) [Chace and Hobbs, 1969]
The multiarticulate, usually whiplike terminal portion of antenule or antenna.
(pl. flagella) [Butler, T. H.]
The often long and multi-articled region distal to the peduncle of the antennule and antennae, and the basis of the uropod. [Holdich and Jones, 1983]
(Taxon-specific: Order Diplostraca) One of two multisegmented branches of antenna; each of the up to 25 segments (articles) bears a row of spine-like setae anteriorly and brush-like setae posteriorly. Number of segments is of taxonomic importance. [Stachowitsch, 1992]
(Taxon-specific: Class Cephalocarida) Aesthetasc. [Stachowitsch, 1992]
(Taxon-specific: Order Cumacea) Distal division of antennule of antenna (peduncle, flagellum). In antennule, one may distinguish a larger outer (main) and smaller inner (accessory) flagellum. Flagellum of antennule bears aesthetascs. (multiarticulate, uniarticulate). [Stachowitsch, 1992]
(Taxon-specific: Order Tanaidacea) Distal division of antennule or antenna (peduncle, flagellum). Antennule may bear two flagella (with distal segments bearing aesthetascs). [Stachowitsch, 1992]
(Taxon-specific: Order Decapoda) Distal of two divisions (peduncle, flagellum) of antennule or antenna; typically paired in the former, unpaired in the latter. Slender, consisting of numerous segments (articles). May also refer to branch of mouthpart. (straight, bent; filiform, fusiform, plate-like; cross section: circular, dorsoventrally flattened, U-shaped; hairy, smooth, spinose). [Stachowitsch, 1992]
(Taxon-specific: Order Amphipoda) Distal division of antennule or antenna (peduncle, flagellum). May bear sensory structures (aesthetascs on antennules, calceoli on antennules and antennae). If two flagella are present on antennule, one distinguishes a larger (primary) and smaller (accessory) flagellum. [Stachowitsch, 1992]
(Taxon-specific: Order Isopoda) Distal division of antennule or antenna (peduncle, flagellum); composed of a varying number of articles. [Stachowitsch, 1992]
Schematic representation of an isopod illustrating morphological terms. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Distal part of antenna or antennule, usually multiarticulate, occasionally reduced to one or a few articles. [Kensley and Schotte, 1989]
(Taxon-specific: Order Isopoda) Narrow distal part of antenna or antennule, usually multiarticulate, occasionally reduced to one or a few articles, without intrinsic musculature. [Wetzer et al. 1997]
(Taxon-specific: Order Mysida) In antennule, pair of elongate branches of peduncle. In antenna, elongate inner branch of peduncle consisting of three- to four-segmented basal section and multisegmented distal section. Also refers to annulate distal part of outer branch (exopod) or thoracopod. [Stachowitsch, 1992]
(Taxon-specific: Order Stomatopoda) Distal section of antennule or antenna (peduncle, flagellum); slender, consisting of numerous segments (articles). Antennule bears three flagella (one dorsal and divided ventral flagella); antenna, one flagellum (on endopod). [Stachowitsch, 1992]
(Taxon-specific: Order Leptostraca) Distal division (peduncle, flagellum) of antennule. Represents inner branch (endopod). May also refer to endopod of antennule. (long with many small articles, small with few large articles). [Stachowitsch, 1992]
(Taxon-specific: Subclass Branchiura) Palp. [Stachowitsch, 1992]
(Taxon-specific: Subclass Copepoda) Multiarticulate distal section of antennule. [Stachowitsch, 1992]
(Taxon-specific: Class Remipedia) Distal section of antennule. One may distinguish a longer dorsal flagellum composed of 11 or 12 segments (articles) and a shorter ventral flagellum composed of 8 articles (in one case fused into a blade-like structure). Each article bears several setae. [Stachowitsch, 1992]
(Taxon-specific: Superorder Syncarida) Distal division of antennule or antenna (peduncle, flagellum). (paired, unpaired) (See also scaphocerite). [Stachowitsch, 1992]
(Taxon-specific: Order Thermosbaenacea) Distal division of antennule or antenna (peduncle, flagellum), paired in the former, unpaired in the latter. (See also aesthetasc). [Stachowitsch, 1992]
(Taxon-specific: Order Euphausiacea) Elongate, multiarticulate distal end of antennule or antenna. Paired in the former, unpaired and representing inner branch (endopod) in the latter. [Stachowitsch, 1992]

Flange

(Taxon-specific: Class Ostracoda) In closing apparatus of valve, ridge-like inner margin formed by projecting outer lamella. Fits into flange groove of opposite valve. (See also list, selvage). [Stachowitsch, 1992]
(Taxon-specific: Class Ostracoda) Ridge along valve margin formed by projection of outer lamella as narrow brim. [McLaughlin, 1980]

Flange groove

(Taxon-specific: Class Ostracoda) Groove-like depression along inner margin of valve. Separates major ridge (selvage) from flange on thickened part (duplicature) of inner lamella. [Stachowitsch, 1992]

Flexor margin

Endopod of Mxp 3, lateral; and endopod of Mxp 3, including basal 2 articles, distal articles omitted, central. Based on Munidopsis. [Baba, 2005]
(Figure only.) [Baba, 2005]
Inner or shorter margin of flexed appendage. [Butler, T. H.]
The inner or shorter margin of a flexed appendage. [Chace and Hobbs, 1969]

Flexor muscle

A muscle which flexes the leg at the MC joint (Fig. 19). [Warner, 1977]

Flexor surface

Opposable surface (face) of flexible podomere of appendage (in opposition to non-opposed extensor surface). [Hobbs and Jass, 1988]
The opposable surface of a flexed podomere of an appendage. [