CRAWFISH AND LOBSTER. 



131 



does not appear separated from the body as in the insects, 

 but is combined with the thorax, and hence this part is called 

 the cephalo-thorax, as in the spiders. The cephalo-thorax is 

 covered by a continuous shield, or shell, called the carapace, 

 while the abdomen is divided into a series of segments. This 

 part can be bent snugly beneath the body {see Fig. 121). 



Fig. 121. — Feebh-Watee Crawfish feom the Mississippi Eitee. 



At the hinder end of the abdomen are live flattened ap- 

 pendages, which serve as fins, by means of which the animal 

 can swim vigorously bactward. (See Fig. 122.) 



Fig. 122.— Taix -op Ceawfish showing Flattened Appendages foe swimming. 



There are two compound eyes in front, which rest upon 

 little jointed stalks, so that the creature can turn them in 

 various directions. 



