390 CRUSTACEA [October 



the form of the second pair of feet,* but Dr. Leach ob- 

 serves that there is no seta to the antennae of that genus. 

 By the characters drawn from the simple coxae, the thick, 

 stout antennae, emarginate lateral angles of the head, po- 

 sition of the eyes, and in fact from the general habit of 

 the body, it seems to arrange naturally with Podocerus, 

 Jassa, C^rapus, Atylus, &c.; from all of which it is suffi* 

 ciently distinguished by the form of the four anterior feet. 

 It is not uncommon on the branches of Fucus, Sertularia, 

 ftcc, in the estuaries of Newjersey, 



Order IV. LiEMODIPODA. Latr. 



Head united to the first segment of the thorax; eye^ 

 two; stemmata two; maxilla four, placed in a transverse 

 line, labiform; branebia vesicular, at the base of the feet> 

 subcaudal none. 



Genus CWRYAAuk. L 



am. 



Body linear. Antenna four, the upper ones with the 

 last segment as long as the three others and articulated, 

 lower ones shorter; anterior pair of feet appearing to 

 arise from the head; branchia globular or oval, substitu- 

 ted for the third and fourth pairs of feet; anus with two 

 little appendices. 



SPECIES. 



1. C. geometrical. Body above glabrous; head with 

 a short acute spine before; hand of the second pair of feet 

 with one acute and one very obtuse tooth. 



Inhabits salt-water bays; common. 



Cabinet of the Acaaemy. 



