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. Retrieved May, 08 2021, from en.wikipedia.org/wiki/Stenolaemata.

Cyclostomatida, or cyclostomes (which also refers to a group of jawless fish called Cyclostomata), are an ancient order of stenolaemate bryozoans which first appeared in the Lower Ordovician. It consists of 7+ suborders, 59+ families, 373+ genera, and 666+ species. The cyclostome bryozoans were dominant in the Mesozoic; since that era, they have decreased. Currently, cyclostomes seldom constitute more than 20% of the species recorded in regional bryozoan faunas.

Cyclostomatida. Retrieved May, 08 2021, from en.wikipedia.org/wiki/Cyclostomatida.