Order II. CHELONIA. 



Quadrate bone immovably united to cranial arches. Dorsal ribs 

 single-headed, the anterior attached between two vertebrae. Body 

 encased in a bony shell. A plastron formed of a small number of 

 elements in addition to the clavicles. No sternum. No teeth ; 

 jaws covered with horny sheaths. Anal opening round or 

 longitudinal. Copulatory organ present, single. 



Oviparous ; eggs with a hard shell, except in the CTielonidce. 



The Tortoises and Turtles of India fall into five Families*. 



Suborder I. THECOPHORA. 



Dorsal vertebrae and ribs immovably united and expanded into 

 bony plates forming a carapace. Parietals prolonged downwards 

 towards the pterygoids. 



Superfam. A. TEIONYCHOIDEA. 



Articulation between the last cervical and the first dorsal 

 vertebra by the zygapophyses only. Marginal bones absent or 

 forming an incomplete series. 



Carapace and plastron without epidermal shields, 



covered with a soft skin Fam. 1. Trionychidae. 



"Superfam. B. CETPTODIEA. 



Centrum of the last cervical vertebra articulating with the 

 centrum of the first dorsal. A complete series of marginal bones, 

 connected with the ribs. 



Digits short ; tail short, with precocious ver- 

 tebrae Fam. 2. Testudinidae. 



Digits short ; tail long ; caudal vertebras mostly 



opisthocoalous Fam. 3. Platysternidae. 



Limbs paddle-shaped, with only one or two claws. 



Marine . Fam. 4. Chelonidae. 



Suborder II. ATHECM. 



Vertebras and ribs free, separated from a bony exoskeleton. 

 Skull without descending processes of the parietal bones. 

 Limbs paddle-shaped, clawless. Marine Fam. 5. Sphargidae. 



* These five families, so far as Indian genera are concerned, may be recog- 

 nized from external characters by use of the following key: 

 Limbs with four or five claws. 



Tail short Testudinidae. 



Tail nearly as long as the shell Platysternidae. 



Limbs with three claws Trionychidae. 



Limbs with one or two claws Chelonidae. 



Limbs without claws , Sphargidae. 



