Page:The Osteology of the Reptiles.pdf/242

224. Carapace united to plastron by strong buttresses. Skull short. Cervical vertebrae for the most part with but one end concave.

Lower Cretaceous. Probaëna Hay, Naomichelys Hay, United States.

Upper Cretaceous. Baëna Leidy, Eubaëna Hay, Boremys Lambe, ? Neurankylus Lambe, Thescelus Hay, Charitemys Hay, ? Polythorax Cope, United States.

Eocene. Baëna Leidy, North America.

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 Neck withdrawn laterally.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.

. Mesoplastron present. No nasals. Vomers present or absent.

Upper Cretaceous. Bothremys Leidy, Taphrosphys Cope, Amblypeza Hay, Naiadochelys Hay, North America.

Eocene. Podocnemis Wagler, Europe, Africa. Stereogenys Andrews, Africa.

Pliocene. Sternothaerus Bell, Pelomedusa Wagler, Africa.

. No mesoplastron. Vomer distinct, the prefrontals separated.

Eocene. Hydraspis, India. Recent South America.

Pleistocene and Recent. Chelodina Fitzinger, Australia.

. Skull roof complete with horn-like protuberances. Very large turtles.

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

Pleistocene. Miolania, Australia.

Head withdrawn in a vertical flexure.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.