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 medium in size, elliptical hexagon, slightly longer than width, (48-56)-60 μm long, (39-48)-50 μm wide, isthmus 14-17 μm wide; semicells semicircular with flattened apex or trapezoid, both sides wavy (about 8 waves), apex flat or slightly convex, side view broad ovoid (Illustrations of The Japanese Fresh-water Algae, 1977).

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

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