ichthyopterygia

from The Collaborative International Dictionary of English v.0.48

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.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Ichthyopterygia \Ich`thy*op`te*ryg"i*a\, n. pl. [NL. See
   {Ichthyopterygium}.] (Paleon.)
   See {Ichthyosauria}.
   [1913 Webster]