The Collaborative International Dictionary of English v.0.48:

Ornithosauria \Or*ni`tho*sau"ri*a\, prop. n. pl. [NL. See
   Ornitho-, and Sauria.] (Paleon.)
   An order of extinct flying reptiles; -- called also
   Pterosauria.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pterosauria \Pter`o*sau"ri*a\, n. pl. [NL.] (Paleon.)
   An extinct order of flying reptiles of the Mesozoic age; the
   pterodactyls; -- called also Pterodactyli, and
   Ornithosauria.
   [1913 Webster]

   Note: The wings were formed, like those of bats, by a
         leathery expansion of the skin, principally supported
         by the greatly enlarged outer or " little" fingers of
         the hands. The American Cretaceous pterodactyls had no
         teeth. See Pteranodontia, and Pterodactyl.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Pterosauria
    n 1: extinct flying reptiles: pterosaurs [syn: Pterosauria,
         order Pterosauria]