Species: Large, ovoid, 120-200 μm long; oral aperture (cytostome) extends almost to the posterior of the cell; a tuft of caudal cilia posterior; contractile vacuole dorsal; macronucleus ovoid and curved (Carey, 1992). 120-200 μm long; posterior cilia 40-50 μm long (Kudo, 1966). Body elliptical; long cytostome 3/4 body length; with large undulatory membrane on left oral margin; macronucleus kidney-shaped, near rear end; fresh water (How to know the protozoa, 1979).

50 μm 100 μm 150 μm; x 400

Images of collecting locality: Tane-ike (pond), Togakushi highland, Shinano town, Nagano Pref., Japan, May 21, 2006 by Y. Tsukii