ASTACUS NIGRESCENS, 245 
There are no cervical spines, and the middle part of 
the cervical groove is angulated backwards instead of 
being transverse. 
Fig. 62. A & D, Astacus torrentium; B & E, A. nooilis; C & F, 
A. nigrescens. A—OC, 1st abdominal appendage of the male; D—F, 
endopodite of second appendage (x 3). a, anterior, and 3, posterior rolled 
edge; c, d, e, corresponding parts of the appendages in each species ; 
J, rolled plate of endopodite ; g, terminal division of endopodite, 
The abdominal pleura are narrow, equal-sided, and 
acutely pointed in the males (fig. 61, F)—slightly 
broader, more obtuse, and with the anterior edges 
