Genus: Ovoid to cylindrical; ciliation uniform; oral basket made up of double trichites which end up deep in ectoplasm; contractile vacuole terminal (Kudo, 1966). Brosse as 3 longitudinal files (Illustrated Guide, 1985). Body ellipsoidal, ovoid or cylindrical in shape; cytostome apical, circular; cytopharynx equipped with well-developed double nematodesmata; somatic ciliation uniform, kinetosomes paired; macronucleus ovoid, reniform or ellongate; as many species descriptions are insufficient, many are indistinguishable (Carey, 1992).
Species: Cell body 200-300 μm long; anterior rounded, posterior tapered; macronucleus spherical (Kahl, 1930).