FIG. 86. Dissection of Fresh-water Crayfish made by removing the 

 exoskeleton with the appendages and the muscles, digestive gland and 

 kidney of the right side (compare with diagram , a 1 ic figure 83, A). 



aa, antennary artery ; ab t abdomen ; an, arus ; b. d, aperture of 

 right digestive duct exposed by removal of gland ; bf. 4, cheliped ; bn, 

 ventral nerve cord ; cs, cardiac division of stomach ; cth, cephalo- 



