\Mos`a*sau"ri*a\, n. pl. [NL. See {Mosasaurus}.]
(Paleon.)
An order of large, extinct, marine reptiles, found in the
Cretaceous rocks, especially in America. They were
serpentlike in form and in having loosely articulated and
dilatable jaws, with large recurved tteth, but they had
paddlelike feet. Some of them were over fifty feet long. They
are, essentially, fossil sea serpents with paddles. Called
also {Pythonomarpha}, and {Mosasauria}.