O.CopuUfory Organs 



FIG. 91. Typical appendages of the Fresh-water Crayfish, placed in the same 

 position, with the protopodite (pr) and epipodite (ep) downwards, the endopodite 

 (en) to the left, and the exopodite (ex) to the right, (x ij.) 



The protopodite is typically formed of two podomeres (pr. i, fr. 2), the endopodite 

 of five (en. i-en. 5) : a gill (g) may be attached to the epipodite. 



The three proximal segments of the antennute are marked 1-3, its flagella fl. I 

 and fl. 2 ;*the distal end of the endopodite of the antenna is a flagellum (fl). 

 (The tufts of threads in 7 and 8 are very long setae which extend between the 

 gills.) (From Parker and Harwell's Zoology, after Huxley.) 



The structure of these appendages is best understood 

 by a consideration of the third maxilliped (Fig. 91, 7). 

 The main portion of the limb is formed of seven podo- 



