Genus: Body more or less ovo-cylindrical; rigid with spirally striated pellicle; often with a short posterior spinous projection; stigma sometimes present; discoidal chromatophores (chloroplasts) numerous and marginal; paramylum bodies usually large and ring-shaped, laterally disposed; without pyrenoids; fresh water (Kudo, 1966). Species: Body 20-40 μm long (Kudo, 1966). Ovoid with short anterior process and a longer posterior spine; fresh water (How to know the protozoa, 1979).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No. 3, Iyari marsh, Omachi city, Nagano Pref., Japan, June 1, 2008 by Y. Tsukii