PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 427 



the eye-stalk and nearly twice as long as the penultimate segment. The 

 major flagellum is as long as the ultimate segment of the peduncle, the 

 basal portion of about eight segments, the terminal portion three times 

 as long and of about five subequal and very slender segments. Tlie 

 minor flagellum is about half as long as the major, and composed of 

 about six segments. The antennae are very much as in H. socialis. 



The chelipeds are nearly equal in length and similar to those of JT. 

 socialise but in the right cheliped the inner edge of the upper surface of 

 the carpus is angular, and armed with a regular series of twelve to eight- 

 een small spines, while the outer edge is rounded and unarmed ; and 

 the prehensile edge of the dactylus is armed with two irregular and in- 

 distinct teeth, corresponding with two irregular emarginations in the 

 edge of the digit;d portion of the propodus. In the left cheliped the 

 outer edge of the upper surface of the carpus is slightly rounded and 

 scarcely at all sx)inulous, while the inner edge is armed as in the right 

 cheliped. The left chela differs from that of ^. sociaUs in having the 

 digital portion of the propodus considerably stouter than the dactjlus, 

 particularly toward the base. 



The ambulatory legs are proportionally as long but more slender than 

 in H. socialis ; in both pairs the dactylus is longer than the ])ropodus, 

 curved slightly near the tip, about sixteen times as long as broad, sparsely 

 ciliated along the upper edge, and very slightly setigerous along the 

 lower. 



The feynale differs from the male as in S. sociaUs, but to a very much 

 less extent, the chelipeds and ambulatory legs being onl^' a little shorter 

 than in the male, and the right cheliped only a little less stout and a 

 little more like the left than in the male. 



The eggs are few and nearly as large as in if. sociaUs. 



Measurements. 



Length from front of oarapax to tip of abdomen 



Lensith of <?arapax alont; median line 



Li'nsth of car;ipax from front to cervical suture 



Breadth of carapax in front , 



Length of cycstallcs 



Greatest diameter of oyo 



Length of pcckiuele of "antennnla 



Length of ultimate segment of the same 



Length of peduncle of auoenna beyond front 



Length of ullimaic segment of peduncle of antenna 



Length of right cheliped 



Length of carpus 



Length I if propodus 



Breadth of propixUis 



Length of dactylus 



Length of left cheliped 



Length (if carpus 



Len;;tb of prepydus 



Breadth of propodus 



Langtii of dactylus 



Length of first ambulatory leg, right side 



Length of p:o;)odus 1 



Lengih of daetylus 



Lengf li ot second ambul?tory leg, right side 



Lenuth of propodus 



Length of d.ic.ylas 



