Genus: Oral polykinetids straight, never sigmoid (Illustrated Guide, 1985). Small, ovoid or pyriform, anterior pointed; cytostome anterior 1/3 of body where an undulating membrane on the right and three small membranelles on the left; macrostome forms with large buccal ciliation; somatic ciliation complete; a contractile vacuole terminal; a spherical macronucleus central (Carey, 1992). Species: