330 
THE VOYAGE OF H.M.S. CHALLENGER. 
The carapace in this specimen is a little longer than broad ; the single chelipede 
remaining is very slender. In all particulars this specimen agrees very closely with the 
description of S. I. Smith. 
Ethusa orientalis, n. sp. (PI. XXVIII. fig. 1). 
Carapace slightly longer than broad, depressed, everywhere granulated, on the dorsal 
and inferior surface, with the cervical and cardiaco-branchial sutures strongly defined. 
The front is divided by a triangulate median sinus into two lobes, each of which is tipped 
with two spines, so that the front is quadrispinose, and there is a strong triangulate tooth 
or lobe at the exterior orbital angle, which projects forwards to a level with the frontal 
teeth; the lateral margins of the carapace are straight and converge slightly to the front 
as in other species of the genus. There is no distinct epistoma. The post-abdomen (in 
the male) is distinctly seven-jointed; the terminal segment triangulate and subacute. 
The eye-peduncles are subcylindrical and small. The bases of the antennules are 
moderately dilated, and are not armed with distal spinules. The basal joint of the 
antennae is slender, and although more elongated than in some other species does not 
attain the front. The exterior maxillipedes are granulated and are shaped as in other 
species of the genus, i.e., the ischium of the endognath is slightly produced at its antero- 
internal angle and the merus is rounded at the antero-internal angle and obliquely 
truncated along the antero-internal margin ; the exognath is very slender. The chelipedes 
(in the male) are either subequal or unequal, smooth, with the merus very obscurely 
trigonous, carpus short, the larger palm somewhat dilated and compressed, and rather 
longer than the fingers, which are distally acute and not denticulated on the inner 
margins; the palm of the smaller chelipede (or of both chelipedes in one specimen) are 
very slender, not thicker than the wrist. The legs of the second and third pairs are 
moderately robust and elongated, but less slender than in the species of the subgenus 
Ethusina, the dactyli are but very little longer than the penultimate joints ; those of the 
fourth and fifth pairs are short and moderately robust, with very small dactyli. 
Both the specimens are unfortunately very imperfect. 
Two male specimens were collected at the Fiji Islands, in 310 fathoms, Station 173a, 
in lat. 19° 9' 32" S., long. 179° 41' 55" E. 
The specimen with unequal chelipedes, which is slightly smaller than the other, 
measures as follows : — 
Adult $ . 
Length of carapace, . 
Breadth of carapace, about 
Length of larger chelipede, 
Length of third leg, . 
Length of fourth leg, 
Lines. 
7 
n* 
23 £ 
8 * 
Millims. 
16 
15 
24 
49-5 
18 
