ARTHROPODA. 



85 



Fig. 25. 



Fig. 26. 



Fig. 25 DORSAL and Fig. 26 VENTRAL VIEW or MALE CRAYFISH. r, Bostrnm; 

 c.gr, cervical groove ; x , placed on branchio-cardiac groove ; br, bran- 

 chiostegite ; t, tergum ; st, sternum ; pi, pleuron ; ep, epimeron ; pr, 

 protopodite ; ex, exopodite ; en, endopodite ; the appendages and parts 

 of certain segments are numbered 1 to 21, but probably the eyestalks 

 (1) are not appendages, therefore subtract one from each number to 

 make it correct; g.y, excretory opening; m, mouth; a, anus; g.o, 

 genital opening. 



