Crustacea. 



79 



(Callinectes kastatus), often called the " edible crab." Just 

 after they molt they are esteemed good, cooked whole, 

 under the title " soft-shelled crabs." 



Swimming crabs, such as the blue crab, have the last pair 

 of thoracic legs developed as paddles, by means of which 

 they swim sideways with considerable rapidity. In the 



Swimming legs. 



FIG. 51. LADY CRAB, NATURAL SIZE. 



case of crabs that do not swim, the last legs are not flat- 

 tened, but end in a point like the other legs. The little 

 oyster crab is often found in an oyster stew (Fig. 52). 



Development of the Crab. It is very interesting to note 

 that the crab, when first hatched, has nearly the form of 

 the crayfish, with an extended abdomen and a relatively 

 narrow body, but that gradually the cephalothorax widens, 

 and the abdomen becomes folded under the body. Crabs 



