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).
Images of collecting locality:
a wetland at Igashira park, Mooka city, Tochigi Pref., Japan, April 1, 2006 by Y. Tsukii