HARD PARTS OF THE COltMON CRAB. 



175 



epistemum (Fig. 91, p), being anterior to the outer 

 end of its own sternum, and articulating with the basal 

 joint of an appendage. 



h. The Appendages. 



Six pairs of appendages, the third pair of Maxillipeds 

 (Fig. 91, m p^), and five pairs of legs, or pereiopods, 

 (p^,p^, p^, p*, p^), are articulated around the lateral and 

 anterior margins of the sternal plasti'on. 



1. The third maxillipeds (Fig. 91, mp^, and Fig. 92), 

 meet upon the median line in front of the anterior angle 

 of the sternal plastron, and they are flattened so as to 

 form a square operculum, which covers the more anterior 

 mouth parts. 



Fig. 92. 

 Fig. 92. — Outer surface of left third maxilHped of Callinectes hasta- 

 tus; natural size. (Drawn from nature by W. K. Brooks.) 



p. Protopodite. en. Endopodite. ex. Exopodite. /. Flabellmn. 

 I b. Basipodite. ex. Coxopodite. is. Ischiopodite. m. MerojKKiite. 

 e. CarpojKKiite. pr. Propodite. d. Dactylopodite. 



Like the abdominal appendage, or pleopod, this ap- 

 pendage is divisible into three regions, & protopodite (Fig. 

 92, ^), an exopodite (Fig. 92, ex), and an endopodite 

 (Fig. 92, en), but each of these regions is again divided 

 into parts. 



