OEDER I. 



CHELONII, Brogniart. 



Section CATAPHRACTA, Gray. 



CnAR. 1. The body is protected by a bony covering, formed of the vertebra} of the thorax, 

 back, and loins, and by the ribs^ of which there are eight pair, greatly developed and joined 

 to each other by suture. Under this shell or carapace are placed the bones of the shoulder and 

 pelvis ; and beneath it can often be retracted the head and anterior extremities in front, and the 

 posterior extremities and tail behind. 



Char. 2. This bony box is completed below by a broad sternum or plastron, formed of several 

 pieces joined solidly to each other, and most commonly, also, to the carapace or shell. 



Char. 3. The head, neck, and tail are the only movable parts of the spinal column. 



Char. 4. The jaws are covered with a horny substance, and are always destitute of teeth, 

 properly speaking, though their cutting margins are often serrated. 



Char. 5. The nostrils are anterior, approximated, and are simple or tubular. 



Char. 6. The eyes are always furnished with three lids. 



Char. 7. The external meatus of the ear is covered with the skin. 



Char. 8. The tongue is fleshy, short, thick, depressed, and covered with fleshy filaments. 



Char. 9. The lungs are extensive, and are placed in the same cavity with the other viscera. 



Char. 10. The heart is composed of two auricles and of one ventricle, subdivided into two 

 unequal cavities that communicate with each other, so that the current of blood from the lungs 

 and that from the body generally are more or less mingled in passing through the ventricle. 



Char. 11. The stomach is simple and very strong, with thick walls. The intestines are of 

 moderate length, and destitute of a ccecum. 



Char. 12. The eggs are round or oval and the shell more or less firm. 



Char. 13. The young undergo no metamorphosis, but resemble the parent in general form 

 from the time they leave the shell. 



This order in the twelfth edition of the Systema Natur£B of Linnseus comprise donly fourteen 

 species, all united in one genus Testudo ; it now includes about eighty, distributed in several 

 different families and genera. — (Holbrook.) 



FAMILY I. 



EMYDIDJl. Gray. 



Char. 1. The feet are palmate, with distinct toes, five in front and four posteriorly, each pro- 

 vided with a sharp nail. 



