358 CLASSIFICATION OF EEPTILES- 



Family 3. TRTOXYCID^, Gray. Soft Tortoises. 



Feet palmated ; three claws only upon each foot ; the 

 carapace^ or shelly covered with a soft skin^ which is 

 expanded round the eye^ so as to form a fin-like mar- 

 gin ; sternum very small_, thin^ and in parts flexible. 



Trioxyx Geoff. ^Margin of the shields cartilaginous, 

 and the sternum narrow. 



T. ferox Merr. Shaw, Zool. iii. 1. pi. 17. 



Emyda Grav. Marain of the shield with a series of 

 small bones in front and behind _; the hmbs covered, 

 when withdrawn into the shell, by the flaps or 

 valves attached to the sternum. 



Family 4. CHELOXID^, Gray. Turtles, or Sea- 

 Tortoises. 

 Feet in the form of compressed flns ; shell surrounded 

 with a bony margin ; claws variable. 



Cheloxia Gray. Shell covered with horny scales, either 

 depressed or imbricate. 



C. imbricata. Shaw, Zool. iii. 1. pi. 27. 



Sphargis Merr. Shell covered with a coriaceous skin. 

 S. coriacea. Shaw, Zool. iii. 1. pi. 21. 



Family 5. CHELYDRIDiE, Sw. Long-tailed or 

 Crocodile Tortoises. 



Tail very long, sometimes armed with carinated scales ; 

 feet palmated ; sternum unusually small, cruciform ; 

 the symphysis narrow. 



Chelys Bumeril. Tail only moderately long ,• nostrils 

 lengthened, tubular ; snout very broad, depressed ; 

 lips soft ; eyes minute ; head and neck with mem- 

 branaceous appendages ; the latter thick, flat, and long ; 

 sternum narrow, rounded in front, and acute behind.* 

 C. fimbriata. Shaw, Zool. iii. 1. pi. 8, 



* The form of the head and nostrils seems to connect thirwith the 



