Source : Webster's Revised Unabridged Dictionary (1913)

Rudistes \Ru*dis"tes\, n. pl. [NL., fr. L. rudis rough.]
   (Paleon.)
   An extinct order or suborder of bivalve mollusks
   characteristic of the Cretaceous period; -- called also
   {Rudista}. See Illust. under {Hippurite}.