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 slightly longer than width, bay linear, both side separated, bay opening wide, 56 μm long, 50.4 μm wide, isthmus 16.8 μm wide; semicells ellipsoidal or reniform, each corner broadly rounded, apex slightly convex; cell wall covered with granules arranging in horizontal rows at the center of semicells, slightly radial at the periphery (Illustrations of The Japanese Fresh-water Algae, 1977).