l — 



Fig. 17. — Astacvs flvmatUis.—k, one of the podobranchiEe from the 

 outer side ; B, the same from the inner side ; C, one of the arjihro- 

 branchiiE ; D, a part of one of the coxopoditio setae ; E,. extremity of 

 the same seta ; F, extremity of a seta from the base of the podo- 

 branchia ; G, hooked seta of the lamina ; (A — C, x .3 ; D — 6, highly 

 magnified), i, base of podobranchia ; cs, coxopoditio setae ; cxp, 

 coxopodite ; I, lamina, pi. plume, and st, stem of podobranchia ; 

 t, tubercle on the coxopodite, to which the setae are attached. 



