Genus: Body long, rear usually pointed (Illustrated Guide, 1985).
Elogate; snout or neck-like prolongation (proboscis) conspicuous; contractile vacuoles two or more (Kudo, 1966).
Contractile vacuoles usually lie in a row along the dorsal surface (Carey, 1992).
Species: 300 μm long, with a long sharply pointed tail; four large rectangular macronuclei; interkinetal mucocysts present in large numbers; a row of contractile vacuoles lying against dorsal surface (Carey, 1992).
Images of collecting locality:
Futayo-no-ike (pond) near Haguro mountain, Haguro town, Yamagata Pref., Japan, August 3, 2006 by Y. Tsukii