Ascophora

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Ascophora (class Gymnolaemata, order Cheilostomata) Suborder of cheilostome bryozoans in which the tentacles are protruded and withdrawn by means of a hydrostatic organ (the compensation sac). The operculum is hinged in such a way that it controls the flow of water into the interior. The suborder occurs from the Cretaceous to the present.