They can be found under rocks, submerged leaves, and other debris, where they feed on tiny crustaceans, microorganisms, and organic particles. This genus belongs to the order Catenulida, a mainly freshwater group of flatworms, with some marine representatives. This group is different from other turbellarians, with a ciliated, sac-like intestine, simple pharynx, and unpaired gonads. Although most species of protozoans are invisible to the naked eye, they dominate the Earth's environment, occurring everywhere and in an amazing diversity of forms and functions. Actinophrys - These heliozoans are found most often in freshwater, floating in the open water amongst reeds and filamentous algae.
Heliozoans are spherical and are frequently enveloped by a shell made of silica or organic material.
Bursaria - Bursaria is one of the ciliates, considered the most complex of the protozoan groups. Coleps is a rapid swimmer, revolving as it travels and using this motion to bore out chunks of other protozoans it is feeding upon. Euplotes - Euplotes belongs to the ciliate order Hypotrichida whose species are characterized by rows of fused cilia called cirri on the ventral surface. Loxophyllum - A ciliate that lives in freshwater habitats, Loxophyllum preys upon rotifers and other ciliates. It has groups of trichocysts in wart-like protuberances that it uses for immobilizing prey.