鱼龙亚纲
Ichthyosauria \Ich`thy*o*sau"ri*a\, n. pl. [NL. See {Ichthyosaurus}.] (Paleon.) An extinct order of marine reptiles, including Ichthyosaurus and allied forms; -- called also {Ichthyopterygia}. They have not been found later than the Cretaceous period. Ichthyopterygia \Ich`thy*op`te*ryg"i*a\, n. pl. [NL. See {Ichthyopterygium}.] (Paleon.) See {Ichthyosauria}.