216 



MANUAL OF ZOOLOGY 



SECT. 



In the male the first and second pleopods (9) are modified 

 into incomplete tubes which act as copulatory organs. The 



en, 3 



tfi- 



5. 2" d Max'ila 6. l" Maxillipe d 



Q.Copulafory Organs lO.Swimming Poor 



ll.Uropod 



FIG. 115. Typical appendages of Astacus. en. / j, podomeres of endopodite ; 

 ep. epipodite ; ex. exopodite ; _/?. flagella ; g. gill ; /;-. /, fir. 2. podomeres of 

 protopodite ; / j, podomeres of axis of antennule. (After Huxley.) 



sixth pair of abdominal limbs (11) are alike in the two sexes : 

 they are very large, both endo- and exopodite having the 



