Cyclostomata \Cy`clo*stom"a*ta\ (s?`kl?-st?m"?-t?), Cyclostoma \Cy*clos"to*ma\ (s?-kl?s"t?-m?), n. pl. [NL., fr. Gr. ky`klos circle + sto`ma, -atos mouth.]

(Zo["o]l.) A division of Bryozoa, in which the cells have circular apertures.

Source: Webster's Revised Unabridged Dictionary (1913)