CKOCODILIA OR CROCODILIANS. 223 



Their eyes have movable eyelids, their ears movable ear- 

 lids, and their nostrils are in the extremity of the snout 

 and capable of being closed by a valve. 



The tail of the Crocodilians is exceedingly powerful, 

 and with it they strike down and sweep into the water 

 large animals upon which they would prey. The Croco- 



FIG. 255. 



Alligator, Alliga'or Mississippiensis, Gray. 



dile immediately seizes its victim and drags it beneath the 

 surface of the water to drown it. By a peculiar arrange- 

 ment the Crocodile can instantly close the entrance to its 

 throat, so as to prevent the ingress of water, and thus, 

 by bringing from time to time the extremity of its 

 snout above the surface, it can with impunity maintain 

 its grip upon the prey and keep it under water. 



The true Crocodiles attain the length of thirty feet ; the 

 Alligators fifteen feet or more. 



Crocodiles have the long "canine" teeth so arranged as to fit into 

 holes in the upper jaw, the hind feet webbed nearly to the toes, and a 

 ridge of projecting scales down the outer border of their hind legs. 



Alligators have the " canine " teeth arranged to fit into a pit in the 

 upper jaw, and they have no ridge of projecting scales on the outer 

 border of their hind legs, and their hind feet are not so completely 

 webbed as those of the Crocodiles. 



