CLASSIFICATION 



653 



Order Crocodilia. 



Crocodilia are character- 

 ized by well-developed limbs, 

 long tail, fixed quadrate 

 bone, and teeth fixed sepa- 

 rately in alveoli. The vari- 

 ous extinct forms, however, 

 do not have all these charac- 

 teristics. 



There are only two fam- 

 ilies of Crocodilia (Fig. 380). 

 Family I. Gavialidae. 



There is only one living 

 species of this family. It is 

 called Gavialis gangeticus. 

 It is found in the River 

 Ganges and other large 

 rivers of India. 



Family II. Crocodilidae. 



This family inludes both 

 old and new world crocodiles 

 and alligators. The latter 

 animals do not grow^as large 

 as the crocodiles. The alli- 

 gator is distinguished from 

 the crocodile by having a 

 broad, rounded snout. 



Order Sauria. (Squamata.) 



These are the lizards 

 and snakes. Their main dif- 

 ferentiating characteristics 

 are: a movable quadrate 



A, grows to weigh 800 pounds; B, 40 pounds; C, bone whi ch permits of a 



***** the tortoise " wide mouth-opening, a trans- 

 verse cloacal aperture and 

 double copulatory organs. 

 Division I. Lacertilia. (Lizards). 



While normally the ordinary forms of lizards are scaly and have 

 four well-developed legs, there are many species which do not have 

 these characteristics. This latter type appear quite like snakes but the 

 bones of the skull always serve to distinguish them. Then too, the 

 lizards have no elastic ligament between the two halves of the lower 

 jaw, as snakes have. 





