Genus: Flattened colonies of 4 cells embedded in gelatinous sheaths; cells nearly sphearical, with two flagella of equal length, a stigma and two contractile vacuoles; a single chloroplast cup-shaped, with a single or several pyrenoids; asexual reproduction by autocolony formation, each cell divides into a daughter colony; sexual reproduction isogamous (Photomicrographs of the Freshwater Algae, vol. 2, 1984). Species: Colonies consisting of 4 cells, up to 20-50 μm in width; cell body pear-shaped, up to 10-22 μm long, 6-16 μm wide. (Photomicrographs of the Freshwater Algae, vol. 2, 1984).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Old Sugata river, Yasuzuka, Mibu town, Tochigi Pref., Japan, May 5, 2008 by Y. Tsukii