Chap, iv.j MOUTH ORGANS OF CRAYFISH. 



123 



There is, in other words, a basal portion and two 

 branches more or less well developed. 



Of all, the most modified is the first of the six, or 

 mandible, for here the basal portion is very strong, 



=3H5k/ * 



B 



en. 



If. . 



Fig. 58. Mouth Organs of the Crayfish. 



A, Mandible ; B, flrst maxilla; c, second maxilla : bp, basipodite ; i,endopodite ; 

 cxp, coxopodite ; p, palp of mandible ; sg, scapliognatliite. (After Huxley .1 



and gives rise to two toothed ridges ; of these the 

 lower projects farther than the upper, and has a more 

 sharply serrated edge ; of the two branches of a 

 typical appendage, the endopodite is alone developed, 

 and that feebly, for it consists only of three compara- 

 tively short joints (palp). 



