Genus: Cell body ellipsoidal-ovoidal with cell wall; Four euqal-length flagella arising from an anterior depression of the cell body; chloroplast cup-shaped with a pyrenoid at the bottom; a single stigma large; two contractile vacuoles at the base of flagella (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000). Species: Cell body ovoidal, 16-23 μm in diam.; anterior depression 1/5-1/6 of the body length; a single circular stigma located at the equatorial line (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: a small stream at Yase Shinsu koen (Yase water park), Minakami town (formerly Tsukiyono town), Gunma Pref., Japan, May 25, 2006 by Y. Tsukii