Genus: Free-swimming; rigid oval; ventral surface convex; dorsal surface with a longitudinal groove; flagella anterior; one long, directed anteriorly; the other shorter and trailing; fresh water (Kudo, 1966). Species: Posterior end truncate or concave; about 22 μm long (Kudo, 1966). Wide lateral groove; second flagellum short, in groove, hard to see; resembles Petalomonas (How to know the protozoa, 1979).

50 μm 100 μm 150 μm; x 400