Bryozoans in this family form encrusting colonies; the autozooids more or less separated except for linking tubular extensions from the proximal region; attached by rhizoids. Lateral walls lightly calcified; all the frontal surface membranous, incorporating an operculum; often with marginal spines. Pedunculate avicularia commonly present. Ovicell often absent.
(Hayward and Ryland, 1998)