224 THE OSTEOLOGY OF THE REPTILES 



Family Baenidae. Carapace united to plastron by strong but- 

 tresses. Skull short. Cervical vertebrae for the most part with but 

 one end concave. 



Lower Cretaceous. Probaena'H.Siy , Naomichelys'H.aiy, United States. 



Upper Cretaceous. Ba'ena Leidy, Eubaena Hay, Boremys Lambe, 

 ? Neurankylus Lambe, Thescelus Hay, Charitemys Hay, ? Polythorax 

 Cope, United States. 



Eocene. Ba'ena Leidy, North America. 



B. Suborder Pleurodira 



Peripheral bones of carapace present. Neck withdrawn laterally. 

 Mesoplastra absent or present. Temporal roof of skull complete or 

 much emarginated. Pubes and ischia suturally united with plastron. 

 Pterygoids not separating quadrates from basisphenoid. 



Family Pelomedusidae. Mesoplastron present. No nasals. Vo- 

 mers present or absent. 



Upper Cretaceous. Bothremys Leidy, Taphrosphys Cope, Ambly- 

 peza Hay, Naiadochelys Hay, North America. 



Eocene. Podocnemis Wagler, Europe, Africa. Stereogenys An- 

 drews, Africa. 



Pliocene. Sternothaerus Bell, Pelomedusa Wagler, Africa. 



Family Chelydidae. No mesoplastron. Vomer distinct, the pre- 

 frontals separated. 



Eocene. Hydraspis, India. Recent South America. 

 Pleistocene and Recent. Chelodina Fitzinger, AustraHa. 



Family Miolanidae. Skull roof complete with horn-like protu- 

 berances. Very large turtles. 



Uppermost (?) Cretaceous. Miolania Owen, South America. 

 Pleistocene. Miolania, Australia. 



C. Suborder Cryptodirai 



Head withdrawn in a vertical flexure. Carapace with marginal 

 plates. Pelvis not united with plastron. Epiplastra in contact with 

 hyoplastra. Pterygoids separating quadrates and basisphenoid. 

 ' [Many genera omitted. — G. K. N.] 



