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).

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640