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. 



cxs 



Fig. 44 — Astaeus flvxicdiUs. — The third or external maxillipede of the 

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

 podobranchia ; cxp, coxopodite ? cxs, coxopoditic setse ; ip, basi- 

 podite ; ex, exopodite ; ip, ischiopodite ; mp, meropodite ; cp, 

 carpopodite ; pp, propodite ; dp, daotylopodite. 



Neglecting details for the moment, it may be said that 

 tlie appendage consists of a basRl portion (fig. 44, cxp, bp). 



