Definitions

Sensory cells on anterior surface of cephalon.
(syn. haft organ, frontal eye) [McLaughlin, 1980]
Sensory cells or setae on front surface of heads on some branchiopods, copepods, and decapods. [Moore and McCormick, 1969]
(Taxon-specific: ) General term for any of several similar sensory organs in head. The different positions of these frontal organs has led to an array of terms for the individual structures, including nuchal or neck organ and, in the older literature, dorsal and ventral frontal organs. All are innervated by brain and considered to represent reduced photosensitive organs. [Stachowitsch, 1992]
Sensory organs adjoining nauplius eye. [Stachowitsch, 1992]
In certain clam shrimp, unpaired, pyriform projection on middorsal surface of head.
(syn. frontal appendage) [Stachowitsch, 1992]
(Taxon-specific: Family Pycnogonidae) pair of sensory organs adjoining nauplius eye on anterior end of head; innervated by brain.
(syn. ventral frontal organ, paired ventral frontal organ) [Stachowitsch, 1992]
One pf several sensory structures represented by setae of anteromedian lobes (rostral plate) of cephalon. [Stachowitsch, 1992]
Unpaired sensory structure located near eye on head; innervated by supraesphageal ganglion and typically developed as tentacle- or filement-like projection. [Stachowitsch, 1992]