Chilostoma \Chi*los"to*ma\, Chilostomata \Chi*lo*stom"a*ta\, n. pl. [NL., fr. Gr. ? + ?, ?, outh.] (Zo["o]l.) 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}.]