Mosasauria

[Sarah]

An order of large, extinct, marine reptiles, found in theCretaceous rocks, especially in America. They were serpentlike inform and in having loosely articulated and dilatable jaws, with largerecurved tteth, but they had paddlelike feet. Some of them were overfifty feet long. They are, essentially, fossil sea serpents withpaddles. Called also Pythonomarpha, and Mosasauria.