THE VERTEBRATES 213 



name and appearance, though seen in nature only by the 

 inhabitants or visitors in tropical and semi-tropical lands. 

 In the United States there are two species of these great 

 reptiles: the American crocodile, living in the West Indies 

 and South America, and occasionally found in Florida; 

 and the American alligator, common in the morasses and 

 stagnant pools of the Southern States. The alligator differs 

 from the crocodiles in having a broader snout. It is rarely 

 more than twelve feet long. The best-known crocodile ia 

 the Nile crocodile, which is not limited to the Nile, but is 

 found throughout Africa. In the Ganges of India is found 

 another member of this group of reptiles, called the gavial. 

 It is among the largest of the order, reaching a length of 

 twenty feet. The crocodiles, alligators, and gavials com- 

 prise not more than a score of species altogether, but because 

 of their wide distribution, great size, and carnivorous habits 

 they are among the most conspicuous of the larger living 

 animals. They live mostly in the water, going on land to 

 sun themselves or to lay their eggs. They move very quickly 

 and swiftly in watei*, but are awkward on land. Fish, 

 aquatic 'inammals, and other animals which occasionally 

 visit the water are their prey. The gavial and Nile croco- 

 dile are both known to attack and devour human beings, 

 and these species annually cause a considerable loss of life. 

 But few such fatalities, however, are accredited to the Ameri- 

 can alligator. 



