Genus: Unicellular; variable in shape; a constriction at the center of the cell body;
mostly longer than wide; flattened; each semicell hemispherical, spherical, ellipsoidal,
rectangular, pyramidal or kidney-shaped; no apical indentation
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species: Cell body 32.3 μm long, 30 μm wide, isthmus 8.6 μm wide; semicells pyramidal with fattened apex; bay closed; granules arranged in 4 rows and about 7 columns, largest 4 granules located at the center of the cell body (Illustrations of The Japanese Fresh-water Algae, 1977).