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:

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Akasaka-numa (pond), Iwatsuki-ku (formerly Iwatsuki city), Saitama city, Saitama Pref., Japan, February 12, 2006 by Y. Tsukii