The Collaborative International Dictionary of English v.0.48:

Bryozoum \Bry`o*zo"um\, n. [NL. See Bryozoa.] (Zool.)
   An individual zooid of a bryozoan coralline, of which there
   may be two or more kinds in a single colony. The zo[oe]cia
   usually have a wreath of tentacles around the mouth, and a
   well developed stomach and intestinal canal; but these parts
   are lacking in the other zooids (Avicularia, O[oe]cia,
   etc.).
   [1913 Webster]