ASTACUS NIGRESCENS. 



245 



There are no cervical spines, and the middle part of 

 the cervical groove is angulated backwards instead of 



being transverse. 



9 



Fig. 62. A & D, Astaens torrentium ; B & E, ^. nohilis ; C & F, 



A. nigrescens. A — C, 1st abdominal appendage of the male ; D — F, 



^ endopodite of second appendage ( x 3). a, anterior, and b, posterior rolled 



edge ; c, d, e, corresponding parts of the appendages in each species ; 



/, roUed plate of endopodite ; g, terminal division of endopodite. 



The abdominal pleura are narrow, equal-sided, and 



n acutely pointed in the males (fig. 61, F) — slightly 



broader, more obtuse, and with the anterior edges 

 12 



