| Abstract |
[OCR of entire article text follows:]
The following communication was received from Mr.
William Stimpson : —
Smithsonian Institution, Washington, D. C, Oct. 1, 1858.
I wish to place on record in the Proceedings of the Society the
existence of a remarkable new form of Brachyurous Crustacean
on the coral reefs at Hawaii. It cannot be properly I'eferred to
any known family, although having perhaps more resemblance to
Pinnotheres than any other known genus, as its integuments ai-e
soft, and the female abdomen of great size, — in fact larger than
the carapax. Its place in the series is pi'obably between Pin-
notheres and Hymenosoma. Four specimens only are in my
possession, which are, unfortunately, all females. They were
collected by the scientific corps of the U. S. North Pacific Sur-
veying Expedition, under the command of Capt. John Rodgers.
It may be called
HAPALOCARCINUS MARSUPIALIS.
The shell or general integument of the body is but little indu-
rated, quite soft and flexible, such as occurs after moulting in
other crabs. The feet however, particularly the chelipeds, are
sufficiently firm. The carapax is leather depressed, smooth, and
glabrous, suboval, longer than broad, narrower in front than be-
hind, somewhat truncated at either extremity, and without teeth
or spines on any part. Front horizontal, straight. Orbits small,
excavated in the anterior margin. Eyes short, oblique, inclining
to longitudinal, and scarcely retractile. Antennula3 very short
and minute, placed at the inner angle of the orbit. The epis-
tome is scarcely distinct, as the lamelliform maxiUipeds reach
nearly to the eyes and antenna?. The buccal area occupies the
whole breadth of the carapax anteriorly, the outer maxillipeds
covering the subhepatic regions. The maxillipeds are loosely
applied, as in some Anomoura, and those of the two sides are
413
separated from each other at the base by the triangular anterior
extremity of the sternum, which is greatly prolonged. In the
outer maxillipeds the ischium-joint is enlarged and dilated within,
while the meros is very small, and slender like the last three
joints or palpus ; the exognath is slender and palpigerous.
The feet are slender and weak, smooth and shaped nearly as
in Pinnotheres. The chelipeds are equal, and about as long as
the ambulatory feet, and twice as thick. Fingers of the hand
nearly straight, longitudinal, and shorter than the palm. Dactyli
of the ambulatory feet all very short, and slightly uncinate.
Sternum very broad and smooth, with the genital orifices rather
wide apart. Abdomen of great size, larger than the rest of the
animal, smooth, but with the segments distinct ; the sides much
expanded and folded inward, forming a kind of pouch for the
reception of the eggs.
Color a dark blue-gray, or "neutral tint." Length of the
carapax, 0.21 ; breadth, 0.165 inch.
Found clinging to the branches of living madrepores, at the
depth of one fathom, in the harbor of Hilo, Hawaii, March, 1856.
They probably feed upon the coral-polypes. |
