Provides information on fossil bryozoans from their first appearance in the early Ordovician, the stenolaemate bryozoans of the early Paleozoic and the rare gymnolaemate bryozoans known only from the Jurassic and Cretaceous.

Several photographs of this small twig bryozoan with rectangular chambers arranged in regular rows along the branch.

Photographs of several nice specimens of branches of this bryozoan including a cross section.