Crocodiles. 5 1 



The land forms included under this order are 

 tortoises, such as the common Greek tortoise, which 

 live on land and have stumpy feet with short nails. 

 The aquatic forms or turtles, such as the green turtle 

 used in making turtle soup, and the hawks- bill turtle 

 used for its ' tortoise shell,' are known by their webbed 

 feet. The largest tortoises of the present day only 

 measure a few feet in length, but in ancient days 

 tortoises reached enormous sizes ; thus the Colosso- 

 chelys, or ,giant fossil tortoise of India, sometimes 

 reached a length of over thirteen feet. Tortoises are 

 slow in growth, and attain to extraordinary ages. 

 They are for the most part vegetable feeders, differ- 

 ing in this respect from most other reptiles. 



28. Order 4, Crocodilia. These, the highest in 

 organisation of the entire class, are inhabitants of the 

 rivers of tropical countries, and are among the largest 

 of living reptiles. T v ey have a rough, hard, scaly 

 coat of epidermis which is placed dorsally on a 

 dermal bony surface. The vertebral column is pro- 

 vided with ribs, and is composed of vertebrae hollow 

 in front and convex behind. The skull is long, and 

 covered with peculiar sculptured markings. The teeth 

 are seated in sockets in one row, and are renewed 

 several times in succession. The heart has a com- 

 plete septum or partition in the ventricle dividing it 

 into two distinct cavities, but the aortic arches still 

 communicate with each other at their base?. The 

 feet are webbed and possess strong claws, and there 

 are dermal glands in the throat secreting a peculiar 

 musky material. The forms included are the croco- 

 diles of the Nile and Indian rivers, with their long 



E2 



