Bryozoa are abundant in some regions; the fenestellids including Fenestella, Polypora, and Archimedes, so named because it is in the shape of an Archimedean screw.
The abundance of bryozoans in specific regions is highlighted, with the fenestellid group (Fenestella, Polypora, and Archimedes) being a notable example known for their unique Archimedean screw-shaped morphology.