odontostome

odontostome, any member of the protistan order Odontostomatida. These small, wedge-shaped, ciliated protozoans were called Ctenostomatida until the name was found also to designate a bryozoan order. Odontostomes are usually found solely in fresh water with a high rate of organic decomposition. Their semicircular, or arc-shaped, back and the sides are covered with firm plates that form a carapace. These organisms are sparsely ciliated and have eight membranelles (cilia fused into flat plates) in the...