Among cyclostome bryozoans, the calcitic skeleton is usually lamellar, consisting of tabular or lath-like crystallites stacked like tiles at a low angle to the wall surface.

Cheilostome bryozoans may exhibit a similar ultrastructure but more commonly have fibrous skeletons consisting of needle-like or bladed crystallites oriented almost perpendicular to wall surfaces.

The skeletal parts of individual feeding zooids - autozooecia - are typically long, curved tubes with terminal apertures which are either circular or polygonal in shape.

All post-Palaeozoic cyclostomes have interzooidal connections via pores in the vertical walls separating adjacent zooids.

Modern cyclostomes exhibit polyembryony: fertilized ova divide to produce multiple, genetically identical larvae which are housed in the spacious gonozooid before being released, swimming for a short period before settling and undergoing metamorphosis to establish new clonal colonies.

Subsequent generations of zooids along the branch then typically return to the normal colony budding pattern.

At the present day cyclostome bryozoans are exclusively marine and stenohaline, with most species living subtidally on the continental shelf.

UK government-sponsored scientific reports in connection with renewable energy in 2014 uncovered the first recordings of Escharoides bishopi and the non-native Fenestrulina delicia in British waters[2] Relative to cheilostomes, they appear to be less numerous and diverse in low latitudes - temperate and arctic environments host almost all of the large species.

Little is known about predation specifically on cyclostomes although it is likely that they are preyed upon by the nudibranchs (sea-slugs), pycnogonids (sea-spiders), echinoids and fishes which consume other marine bryozoans.