Description of Pleuronema crassum
provided by BioPedia
Scuticociliate, 70-120 micrometres long. Ovoid body, slightly flattened, rounded at both ends, sharper in the anterior. Peristome 3/4 as long as the body, with powerful feeding cilia at right edge; mouth small. Large, sail-like undulating membrane on left edge of peristome; this structure can be fully retracted. Somatic cilia long, in longitudinal rows, uniform. Single macronucleus, spherical, in anterior half of the body. No caudal cilium. One contractile vacuole, dorsal in posterior third. Feeds on bacteria. Movements abrupt; rests very placidly while feeding, with undulating membrane spread, then suddenly jumps away. Fresh and salt water.
