Family: Unicells; cell wall present; two flagella (Illustrations of The Japanese Fresh-water Algae, 1977).
Genus: Unicellular, within a large spherical sheath; two equal-length flagella emerging from anterior end; cell body spherical or ellipsoidal, connected with gelatinous sheath by fine filaments; a single chloroplast cup-shaped, with several pyrenoids (Guide book to the "Photomicrographs of the Freshwater Algae", 1998).

lacustris sp. 5 clips Japan, 1999