Genus: Striated sutural regions dorsal and to rear of cytoproct; body tapers to rear from 3 sides (Illustrated Guide, 1985). Broadly rounded anterior end and bluntly pointed narrow posterior end; sausage-form macronucleus; a micronucleus; contractile vacuole middle of body with collecting canals; fresh water (Kudo, 1966).
Buccal structure is well-stained by azure C (Y. Tsukii, 2000).
Species: Cell body 75 μm; long (Kahl, 1930).