Source : Webster's Revised Unabridged Dictionary (1913)

Ornithoscelida \Or*ni`tho*scel"i*da\, n. pl. [NL., fr. Gr. ?, ?,
   a bird + ? a leg.] (Zo["o]l.)
   A group of extinct Reptilia, intermediate in structure
   (especially with regard to the pelvis) between reptiles and
   birds. -- {Or`ni*tho*scel"i*dan}, a.