Genus: Only 1 emergent flagellum; locomotory flagellum directed anteriorly, straight, during swimming;
colourless, phagotrophic; no eyespot; rigid, solitary, ovoid, usually flat, with several keels; freshwater
(Illustrated Guide, 1985).
Oval or pyriform; not plastic; pellicle often with straight or spiral furrow; a single flagellum; many species
Images of collecting locality:
Hazama marsh, Tomita, Ashikaga city, Tochigi Pref., Japan, April 22, 2006 by Y. Tsukii