Genus: Cigar- or foot-shaped; a single macronucleus and 1 to several vesicular or compact microuclei (Kudo, 1966). Anterior rounded or obliquely truncated, posterior rounded or tapered; cell body asymmetrical due to a depression of the ventral surface (oral groove) running from the apex of the cell to about the middle of the body; oral aperture (cytostome) at its posterior end; somatic ciliation uniform; trichocysts present; one or more contractile vacuoles present; macronucleus ovoid or reniform (Carey, 1992). Species: