Genus: Generally ovoid; asymmetrical; plastic or rigid; a slit-like ventral furrow; flagella at anterior end; cytopharynx long; contractile vacuole anterior; nucleus posterior (Kudo, 1966). Lightly striated; trailing flagellum longer than anterior one (How to know the protozoa, 1979). Species:

50 μm 100 μm 150 μm; x 400