Genus: Biflagellate, both arising from anterior end; one directed anteriorly and the other runs backward
over body surface as a trailing (recurrent) flagellum; body plastic (Kudo, 1966).
Small (10-15 μm);
body is generally pyriform to cylindrical
except for an ameboid variable posterior (Illustrated Guide, 1985).
cell body 10 μm long, 6 μm wide,
x 640, Iruma river, Sayama city, Saitama Pref., Japan, January 25, 2004 by Y. Tsukii
31 μm 63 μm 94 μm; x 640