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 small, 18-(19.6-29.4) μm long, 18-(19.6-25) μm wide, isthmus 4.5-(5.6-7) μm wide; semicells somewhat reniform, apex convex, apical view elongated elliptical, with small projections at both sides (Illustrations of The Japanese Fresh-water Algae, 1977).