CLASSIFICATION OF VERTEBRATA 20 



5. Sub-CLASS CHELONIA, Brogniart 



Stereospondylous. Quadrate fixed. Ribs with capitulum 

 only. Two sacral vertebrae. Pentadactyle walking limbs or 

 paddles. Both jaws without teeth, but with horny sheaths. 

 Humerus without entepicondylar foramen. Pubes and ischia 

 forming symphyses. 



Numerous dorsal and ventral dermal bones, forming a 

 carapace and a plastron. 



Cloacal opening longitudinal. Penis anterior, single. 



1. Order Thecophora, Dollo. Dorsal vertebrae and ribs 

 fused with the dermal plates which form a carapace. With a 

 parieto-pterygoidal column. 



1. Sub-order CKYPTODIRA, Dume"ril. Neck, if retractile, 

 bending in an S-shaped curve in a vertical plane. Pelvis 

 not anchylosed with carapace or plastron. 



Chelydridae. Pubic and ischiadic symphyses widely sepa- 

 rated from each other. Plastron narrow, cruciform, without 

 entoplastral plate. Tail long. 



Since Upper Jurassic of Europe and North America. 



Eecent : Chelydra serpentina ; Macroclemmys temmincki. 

 U.S.A. 



Dermatemydidae. Pubic and ischiadic symphyses widely 

 separate. With entoplastral. Short tail. 



Dermatemys. America, since Eocene. 



Cinosternidae. Pubic and ischiadic symphyses in contact. 

 Without entoplastral. 



Cinosternum in Central and North America. 



Platysternidae. Pubic and ischiadic symphyses connected 

 by ligament. With entoplastral. Unique character : jugal 

 completely enclosed by postfrontal, maxillae and quadrato- 

 jugal. 



Platysternum megacephalum. South China to Siam. 



Testudinidae. Pubic and ischiadic symphyses firmly con- 

 nected with each other. With entoplastron. 



Since Eocene : Clemmys and Emys. 



Since Miocene : Testudo. 



Colossochelys atlas. Upper Miocene, Sivaliks. 



