rhynchocephalia

from WordNet (r) 3.0 (2006)

Rhynchocephalia
    n 1: tuataras; extinct forms from middle Triassic [syn:
         {Rhynchocephalia}, {order Rhynchocephalia}]

from The Collaborative International Dictionary of English v.0.48

Rhynchocephala \Rhyn`cho*ceph"a*la\, n. pl. [NL., fr. Gr.
   "ry`gchos snout + kefalh` head.] (Zool.)
   An order of reptiles having biconcave vertebrae, immovable
   quadrate bones, and many other peculiar osteological
   characters. Hatteria is the only living genus, but numerous
   fossil genera are known, some of which are among the earliest
   of reptiles. See {Hatteria}. Called also {Rhynchocephalia}.
   [1913 Webster]