Genus (Stein, 1863 or 1862?): Ovoid; an equatorial furrow marks conical anterior and spherical posterior parts; in the furrow are inserted two (or more) rings of strong cilia; one directed anteriorly and the other posteriorly; with tentacle-like retractile processes around the cytostome (Kudo, 1966).
Species: 20-31 μm long (Kudo, 1966). 20-38 μm long (How to know the protozoa, 1979). 20-30 μm long; anterior conical, posterior globose; nematodemata forked at the tip (Carey, 1992).