Stenolaemata

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.
Stenolaemata were the predominant bryozoan group during the Paleozoic. Some grew as lacy or fan-like colonies that became important reef builders and in some regions form an abundant component of limestones. Their numbers were greatly reduced during the terminal Permian extinction event, but the order Cyclostomatida survives today.
Extant and extinct orders in this class include: