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: Semicells scalariform or depressed pyramid-shaped with flattened apex; cell body longer than its width, 41-46 μm long, 37-40 μm wide, isthmus 15-17 μm wide; cellwall punctated (Illustrations of The Japanese Fresh-water Algae, 1977).