The Collaborative International Dictionary of English v.0.48:

Chilostoma \Chi*los"to*ma\, Chilostomata \Chi*lo*stom"a*ta\, n.
   pl. [NL., fr. Gr. ? + ?, ?, outh.] (Zool.)
   An extensive suborder of marine Bryozoa, mostly with
   calcareous shells. They have a movable lip and a lid to close
   the aperture of the cells. [Also written Chillostomata.]
   [1913 Webster]