Description of Bursaria truncatella

Members of the genus Bursaria are extremely large heterotrich ciliates, from 250-1700 microns in length. Cells are usually slightly yellow or brown. Ovoid in shape, generally with rounded posterior and truncate anterior ends, giving the cells a scoop-like appearence. Slightly dorso-ventrally flattened, with a deep keyhole-shaped peristome begining at the anterior and terminating in the central part of the cell. This allows Bursaria to ingest large particles such as diatoms and dinoflagellates. Oral ciliature comprises of a prominent adoral zone of membranelles which spirals into the huge buccal cavity. In addition, a long row of fragmented kineties are located on the right wall of the buccal cavity. Somatic ciliature is uniform, densely ciliated, consisting of longitudinal kineties. There are numerous small contractile vacuoles. Typically one band-like macronucleus. Habitat and distribution: planktonic, freshwater and marine, world-wide. Not uncommon.