O.CofJuld^ory Organs lO.Swimmlng Fool- 



U.Uropod 



Fig. 84. — The pi-inclpal appendages of the Frcsh-water Crayfisli, placed in tlie 

 same position, with the protopodite (/r) and epipodite (t'/) downwards, the 

 endopodite {en) to the left, and the exopodite (f.r) to the right. 

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



of five {en. i — ctt. 5) ; a gili {g) may be attached to the epipodite. 

 The three proximal segments of the antennule are marked r — 3, its flagellar?, t 

 and_y^. 2 ; the distal end of the endopodite cA the antenna is a flagellum {Ji). 

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

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



- The structure of these appendages is best understood by 

 a consideration of the third maxiiliped (Fig 84, 7). The 



