164< THE MORPHOLOGY OF THE COMMON CRAYFISH. 



The third maxillipede is one of the most complete of 

 these appendages, and may be advantageously made the 

 starting point of the study of the whole series. 



Fig. ii—AstacnsJlm-iatilis. — The third or external maxillipede of the 

 left side ( x 3). e, lamina, and br, branchial filaments of the 

 XX)dobranchia ; exjj, coxopodite ; cxs, coxopoditic setse ; bjJ, basi- 

 podite ; ex, exopodite ; ij), ischiopodite ; w^?, meropodite ; c/7, 

 carpopodite ; 2U^) propcdite ; dj), dactylopodite. 



Neglecting details for the moment, it may be said that 

 the appendage consists of a basal portion (fig. 44, cxjj, hp), 



