Genus: Colony within a gelatinous bag; cells uniformly arranged at the peripheral matrix; cell body spherical or ellipsoidal with 2 pseudo-flagella; 2-4 cells form a small subset; a single chloroplast cup-shaped, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Small colonies planktonic or large ones attached to other substrates (Illustrations of The Japanese Fresh-water Algae, 1977). Species: getatinous sheath cell body spherical, 6-12 μm in diam., planktonic

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Kitamoto nature observation park, Kitamoto city, Saitama Pref., March 21, 2006 by Y. Tsukii