294 VERTEBRATES: REPTILES. 



CROCODILID^:, OR CROCODILE FAMILY. This Family 

 comprises the Crocodile of the Nile and the Gavial of 

 the Ganges, bulky reptiles, that attain the length of 

 thirty feet, and the Alligators of America. 



The Genus Alligator Alligators has the muzzle 

 broad, obtuse, and greatly resembling that of the pike. 

 The teeth are unequal, the fourth lower ones largest, and 

 entering into holes in the upper jaw, and the toes semi- 

 palmate. Alligators are found from the Carolinas to Para- 

 guay, and within these limits there are several species. 



The Common Alligator, A. mississippiensis, Gray, of 

 the Southern States, attains the length of fifteen feet or 



Fig. 156. 



Alligator, A. mississippiensis, Gray. 



more. It is exceedingly voracious, devouring all kinds 

 of animal substances, and is particularly attracted by fish, 

 muskrats, dogs, ducks, or other animals in motion. 



long, the femur thirty-three inches in length. The Hylceosaiirus was twenty 

 feet long ; and the Mosasaurus, twenty-five feet. The Ichthyosauri were 

 ten to forty feet long, with paddles adapting them for swimming ; and the 

 jaws were in some cases six feet long, and the cavity for the eye fourteen 

 inches in diameter. The Plesiosaiiri were also swimmers, twenty-five to 

 forty feet long, with the neck long, snake-like, and containing twenty to forty 

 vertebrae. The Pterodactyli were flying Saurians, a foot long, with a spread 

 of wing of about three feet. These strange forms, and others, represented 

 by many species, are found in England and on the continent of Europe. 



