GAMMARID^. 51 



ever, they are not soldered. The maxillipeds are un- 

 guiculate. The four anterior pairs of coxas are largely 

 developed. 



This family consists of several subfamilies, which 

 differ from each other in more or less important points. 

 The superior antennae are generally subequal to the 

 inferior, and bear a secondary appendage at the base 

 of the flagellum. This peculiarity, although occasion- 

 ally absent in the adult state, is, we believe, invariably 

 found in the young. One or both pairs of the fore-legs 

 or arms have subchelate hands.* 



Sub-family.— STEGOCEPHALIDES. 



Antennse more than one-fourth the length of the animal, sub- 

 equal. Coxae of tlae second pair of gnathopoda, and of the first 

 and second pairs of pereiopoda monstrously developed. 



In some genera the coxa? of the first pair of legs are 

 rudimentary, or, at least, not developed into scales ; 

 whereas the second is always large, covering the pre- 

 ceding when not squamiform. The hands are subchelate, 

 and the caudal appendages are styliform. The middle 

 piece of the tail is always single. 



This sub-family was established by Dana under the 

 name of Stegocephalin^, for the reception of Kroyer's 

 genus Stegocep/ialus. But there are several other genera 

 which evidently fall within its definition. The principal 

 feature, and one easily recognizable, is, the large size of 

 coxse of the first two pairs of walking legs. These are 

 so monstrously developed, that the animal has the power, 

 when rolled up, of protecting, under this shield-like 



* By a subchelate hand is meant one in which the finger folds upon the 

 hand, but in which the inferior angle of the palm is not pi'oduced iato an an- 

 tagonistic thumb. 



E 2 



