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 in size, 35-42 μm long, 28-36 μm wide, isthmus 8.5-13 μm wide, L/W=1.25; semicells semicircular, margins crenated with 8 projections; two granules present on each projection, side view rectangular, convex at the center, apical view elliptical (Illustrations of The Japanese Fresh-water Algae, 1977).

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