Genus: Slightly plastic; pellicle with 8 longitudinal ridges; two unequal flagella anterior (Kudo, 1966). Ovoid, pointed at rear; notched at anterior; eight longitudinal ridges; short flagellum 1/4 length of of longer onel; both anterior; fresh water (How to know the protozoa, 1979).

T. octocostatus Stein: 35-63 μm long; fresh water (Kudo, 1966). Ovoid, pointed at rear; notched at anterior; short flagellum 1/4 of longer one, both held anteriorly in locomotion; fresh water (How to know the protozoa, 1979).