HISTORY OF THE ALLIGATOR. 153 



erful and very peculiar animal does there. And it is for a 

 similar reason, rather than for any urgent systematic 

 necessity there is for it, that we have resolved to divide 

 the family, or perhaps, systematic ally speaking, the genus, 

 into the three popular sections of alligators, crocodiles, and 

 gavials. By this means we shall be able to render each 

 group an index to a certain portion of the work, equally 

 interesting and peculiar in all its characters. 



The most remarkable distinguishing character of each 

 of these groups is the shape of the head. The gavials 

 have it the most produced, the crocodiles the next, and the 

 alligators have it shortest. In them the length of the 

 jaws from the articulation is only one half more than the 

 greatest breadth. The teeth have a ragged appearance, as 

 some of them are long and others short. There are never 

 fewer than nineteen in each side of either jaw, and some- 

 times two more in each side of the under one. These 

 grow with the growth of the animal ; and receiving cavi- 

 ties are formed for them in the upper jaw, especially from 

 those fourth from the front, which are longer than any of 

 the others. The body is low and flattish ; the hind legs 

 are nearly round in their section, and have no membrane 

 on the sides ; the webs of the toes also extend only half 

 the length; and the holes behind the orbits, which are 

 understood to secrete a musky fluid in the crocodiles, are 

 small and obscure, or wanting. 



From the structure of the feet, and the want of fringed 

 or pectinated membranes on the hind legs, which are both 

 a lessening of the pelagic structure, alligators keep more 

 to the fresh waters, the rivers and lagunes, than the croco- 

 diles ; so that those in the bays of the West India islands, 

 though popularly known as alligators or caymans, are 

 rather to be considered as crocodiles, even in the popular 

 sense of that term. 



There are four specimens or more, all natives of the 

 warmer parts of the American continent ; but varying in 



