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.
Bryozoans are widespread in certain areas; the fenestellids, including Fenestella, Polypora, and Archimedes, which is named after its shape resembling an Archimedean screw.