Phylum of Ectoprocta. Very small (< 1 mm) sessile invertebrates living in colonies that can cover fixed substates and have mostly a structure reminiscent of moss (hence "moss animals"). Colonies consist of individuals specialized in different ways, e.g., the zooids, which have a protruding lophophore with a
circle of tentacles for collecting food particles. The body contains a large coelom and a U-shaped gut, but other organs are absent. This phylum is one of the most important phyla with some 4000 extant species. Bryozoans live in freshwater as well as the marine environment, but mainly in coastal waters. Some species occur as deep as 8000 m. They have a rich fossil record.

Alternative form for bryozoa : bryozoans.