208 STALK-EYED CRUSTACEA. 
penultimate thoracic legs carry an epipod but not a podobranchia, the three 
pairs of chelate legs are furnished with small epipods and also with a podo- 
branchia. This specimen doubtless belongs to Bate’s genus Gennadas which, 
it seems to me, hardly deserves to be separated from Benthesieymus. Smith’s 
genus Amalopencus* closely resembles Gennadas in its general form, but is said 
to lack the podobranchiz throughout the series of thoracic legs. 
The other specimen, from Station 2638, is in a still worse state of preser- 
vation. It was taken in the Tanner net towed at a depth of from 500 to 570 
fathoms over a bottom of 622 fathoms, off Guaymas. 
Famity SERGESTID. 
SERGESTES M. Epw. 
Ann. Sci. Nat., XIX. 346, 1830. 
Sergestes inous Fax. 
Plate LI, Fig. 2-2". 
Bull. Mus. Comp. Zodl., XXIV. 216, 1893. 
Integument soft, membranaceous. Carapace devoid of spines. Gastro- 
hepatic groove distinct across the dorsum. Rostrum short, triangular, blunt 
at the tip, bounded on each side by a distinct sulcus. The orbital area of the 
carapace is likewise circumscribed by a shallow sulcus which unites poste- 
riorly with the anterior part of the cervical suleus. The upper limit of the 
branchial area is defined by a prominent ridge which gives off from its ante- 
rior end an inferior branch obsolescent before reaching the posterior border 
of the carapace. The excurrent branchial orifice is bounded externally by a 
shallow concavity in the antero-lateral margin of the carapace. 
The abdomen is unarmed, the terga of the several somites rounded 
above, the pleure with rounded and ciliated lower margins. A distinct 
longitudinal groove courses over the side of the fourth, fifth, and sixth 
somites of the abdomen, beginning at the posterior end of the anterior third 
of the fourth somite and ending a little way in front of the posterior border 
of the sixth. The sixth abdominal somite is once and one half as long as 
the fifth and about equal in length to the telson, which is sulcate above and 
on each side and tipped by a small acute spine. 
The eye-stalks are shorter than the proximal segment of the first pair 
* Bull. Mus. Comp. Zool, X. 86, 1882. 
- “4% be 
