Pig. 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 diagrammaiic figure 83, a). 



aa, antennary artery ; ad, abdomen ; an, anus ; d. 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- 



