18 CLASS REPTILIA. 



The Soft Tortoises. Trionyx. Geoff. 



Have no scales, but only a soft skin to envelope their 

 carapace and plastron, neither of which is completely 

 supported by the bones, the ribs not reaching the 

 edges of the carapace, and not being united together 

 but in a portion of their length, the part analagous to 

 the sternal ribs being formed of a simple cartilage, 

 and the sternal pieces partly indented, as in the sea- 

 tortoises, not filling all the lower face. It is easy to 

 perceive, after death, through the dried skin, that 

 the surface of the ribs is very rugged and uneven. 

 The feet, as in the fresh-water tortoises, are palmate, 

 without being elongated ; but three of their toes only 

 are provided with claws. The horn of their beak is 

 clothed externally with fleshy lips, and their nose is 

 prolonged into a small trunk. The tail is short, 

 and the anus pierced under its extremity. They 

 live in the fresh water, and the flexible edges of 

 their envelope assist them in swimming. 



The Tyrse^ or Soft Tortoise of the Nile. Testudo 

 Triunguis. Forsk. and Gm. Trionyx ^gyptia- 

 ciis. Geoff. Ann. du Mus. xiv. 1. 



Sometimes three feet long; green, spotted with 

 black, and the carapace not very convex. It de- 

 vours the little crocodiles at the moment when they 



