Bowerbankia gracilis Leidy, 1855

Ctenostome bryozoa like this one have an uncalcified zooecium and a simple aperture; there are no avicularia or external ovicells. In this and some other ctenostomes the zooecia attach to a creeping stem called a stolon, which is actually a modified zooecium. In Bowerbankia, the zooecia arise irregularly from an erect or creeping stolon. This example is growing along a section of the branching ctenostome bryozoan, Anguinella palmata.