THE LIZARD AND ITS ALLIES 279 



moccasin or black moccasin, which inhabits the Southern 

 States, and gives no warning noise as does the rattlesnake. 

 The copperhead of the eastern half of the United States is 

 also dangerous, bnt is mostly confined to wooded, moun- 

 tainous regions. The rattlesnake was once common over 

 the whole of the Northern States as far west as the Rocky 

 Mountains, but it is now nearly exterminated in well- 

 settled districts. Related to these are the venomous 

 vipers of Europe. 



The order Crocodilina contains only some twenty species, 

 distributed in three genera. The gavial is the crocodile 



FIG. 263. Head of Alliyaior mississippiensis, the Mississippi alligator. 

 From Leunis. 



of the Ganges River. It captures even large mammals 

 and man. The crocodile in the strict sense is found in the 

 Nile and other African rivers, in certain countries on the 

 western border of the Pacific, and in northern South 

 America, Central America, and the Antilles. The American 

 alligator, which has a different arrangement of the denti- 

 tion from the crocodiles, occurs in seven slightly differing 

 species, all of' which are South American excepting the alli- 

 gator of our Southern States. It feeds on fish, and attacks 

 horses and even man (Fig. 263). 



