Genus: Body blunt at rear; kineties spiralled when body contracts (Illustrated Guide, 1985).
Species: 200-300 up to 700 μm long; peristome 1/4 the body length; macronucleus oval; posterior end drawn out (Kudo, 1966). 700 μm long; tail region attenuated; peristome less than 1/4 the body length; macronucleus single and ovoid (Carey, 1992).
Images of collecting locality:
No.1, Karakemi marsh, Yasaka, Omachi city (formerly Yasaka village), Nagano Pref., Japan, June 4, 2007 by Y. Tsukii