O.CopuIafory Organs lO.Swimming Poor 



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

 position, with the protopodite (pr) ""' epipodiu- (cp) downwards, the endopoditc 

 (en) to the left, and the exopodite (<) to tin- ri.vht. (X i}.) 



Tin- protopd.lite is typically fonm-d of two ptxlomeres (pr. i, fr. 2), the endopodite 

 of five (i-ii. i en. 5) ; a dH (.c) in iv ! attached to the cpipodite. 



Th" Hirer prc-xiinal sr-im-nt^ of the antenmile aie marked 1-3, its flagella fl. I 

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

 (The Hilts of threads in 7 and .s are \ ( i\- long seta? which extend between the 

 gills.) (From Parker and HaswelTs Zoology, after Huxley.) 



The structure of these appendages is best understccd 

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

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



365 



