208 



STALK-EYED CRUSTACEA. 



penultimate thoracic legs carry an epipod but not a podobrancliiaj tlie 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 Benlhcsicpnus. Smith's 

 genus Amalopcneus^ closely resembles Gennadas in its general form, but is said 

 to lack the podobranchise 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. 



Family SBRGESTIDiE. 



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SERGESTES M. Edw. 



Ann. Sci. Nat., XIX. 3dG, 1830. 



Sergestes inous Fax. 



Flak LL, Fig. 2-2". 



Bull. Mus. Comp. Zool, XXIV. 216, 1893. 



Integument soft, membranaceons. . 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 sulcus. The upper limit of the 

 branchial area is defined by a prominent ridge which gives off from its ante- 



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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 anterodateral margin of the carapace. 



The abdomen is unarmed, the terga of the several somites rounded 

 above, the pleural with rounded and ciliated lower margins. A distinct 



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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. 80, 1882. 



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