CROCODILIA 195 



modern crocodiles can hardly be called, as a group, purely aquatic 

 reptiles, we shall rind it of interest, because of their intimate rela- 

 tion to the older and more strictly marine forms, to speak of them 

 somewhat in detail. 



MODERN CROCODILES, EUSUCHIA 



The crocodiles of the present — and we use the word in the 

 technical sense of Crocodilia — because of their general resemblance 

 to the lizards, or true "saurians," were classed with them by the 

 older naturalists, whence comes the popular name alligator, a cor- 

 ruption of the Spanish el la gar to, or "the lizard," given to some of 



Fig. 98. — Senegal crocodile. (By permission of the New York Zoological Society) 



the South American forms by early explorers. But this resem- 

 blance is a superficial one only, as was early recognized by com- 

 parative anatomists. The crocodiles, indeed, are only remotely 

 related to the lizards. 



The head or cranium is flattened and broad, the facial part or 

 snout sometimes greatly elongated and slender, and the external 

 nostrils are always situated at the front end. The bones of the 

 upper surface of the cranium and face have many pit-like depres- 

 sions. The neck is short and stout, and but little movable. The 

 body is somewhat depressed and flattened, not cylindrical and 

 slender, as in the more typical water reptiles. The tail is much 

 elongated and compressed, forming a powerful means of propulsion 



