Stenolaemata are a class of marine bryozoans. This class originated in the Ordovician, and members still live today. All extant species are in the order Cyclostomatida. These animals are stationary suspension feeders that live on the ocean floor. The individuals in the colony may be tubular, conical, or sac-shaped. Each individual, or zooid, may extend from the colony at an angle, extending its tentacles to feed. The fossil genus Batostoma in the order Trepostomatida existed in monticular colonies. Extant and extinct orders in this class include: