Umbonulidae

Colony encrusting; or erect bilaminar. Frontal shield with conspicuous marginal areolar pores, bordered by interareolar ribs. Secondary orifice simple, flared, or with one or more denticles on its inner face. Oral spines present or absent. Avicularia present, adventitious. Ovicell hyperstomial, perforate; or absent. Vertical walls with multiporous septula.

(Hayward and Ryland, 1999)