DECAPODA. 183 



pedicles are susceptible of being entirely retracted within their fos- 

 sulce, and are protected posteriorly by a dentiform projection, or 

 angle, of the lateral edges of the shell. The second joint of the pe- 

 duncle of the lateral antennae is much larger than the following one ; 

 they are terminated by a very short stem resembling an elongated 

 stylet. 



Hyas, Leach. 



Lateral edges of the shell dilated behind the ocular cavities, which 

 are large and oval ; external side of the second joint of the lateral 

 antennae compressed and carinated ; ocular pedicles, when erected, 

 entirely exposed. The body is sub-ovoid*. In the 



LiBiNiA, Leach, 



The ocular fossuloe are very small and nearly orbicular, and the 

 ocular pedicles are very short, and but very slightly exertile. The 

 second joint of the lateral antennae is cylindrical, and not compressed, 

 or but very slightly so. The body is nearly globular, or triangular. 



We will unite the Doclcea and the Egeria of Leach to his Li- 



BINLE. 



In his Libiniee, properly so called f , the claws of the males are 

 thicker than the two following feet, and almost as long. The length 

 of the longest does not exceed twice that of the shell. 



The claws of the male Doclaea % are much shorter than the two 

 following feet. The length of the latter is hardly more than once 

 and a half that of the shell, which is nearly globular and always co- 

 vered with a brown or blackish down. 



In the Egerise § the claws are filiform, and the hands much elon- 

 gated and ahnost linear. The following feet are five or six times 

 longer than the shell. The body is triangular. 



Having reviewed all the sub-genera of this tribe 'n\ which the feet 

 subsequent to the claws are of a similar form, and in which the tail, 

 of the females at least, and most generally in both sexes, is composed 

 of seven complete joints or segments, we now pass to those in which 

 it never consists of more than six. The feet are usually long and 

 filiform, as in the last sub-genera. With the exception of the Lep- 

 topi, these Crustacea are almost removed from the preceding by the 

 form of the third joint of the external foot-jaws. It is proportionally 

 narrower, and contracted at base, and the ensuing joint appears to 

 be inserted at the middle of its superior margin, or more externally. 

 The following sub-genus differs from those which succeed to it, in 

 the tail of the males, where we only find three segments. The form 

 of the third joint of the external foot-jaws appears to me the same as 

 in the preceding sub-genera. 



* Cancer amneus, L. ; Leach, Malac. Brit., XXI, A; Herbst., XVII. 59; — 

 Hyas coarctata, Leach, lb., xxi, B. 



t Libinia canalicidata, Say, Journ. Acad. Nat. So. Diilad. vol. I, p. 77, iv, 1; 

 — L. emarginata , Leach, Zool. Misc., cviii. 



X Docltea Rissonnii, Leach, Zool. Misc. Lx.xiv. The Inachus ovis and the T. 

 hybridus, Fab., should be referred to it. 



§ Egeria indica, heach, Zoo\. Misc., Ixiii; Inachus spinifcr, Fab. 



