Source : Webster's Revised Unabridged Dictionary (1913)

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

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}}.

   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}.