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 Subgenus [Eucosmarium]: Cell body dorso-ventrally compressed, with strong constriction at the center, transverse section elliptical or diamond-shaped. Section [Quadratiformes]: Cell surface smooth; semicells rectangular (Illustrations of The Japanese Fresh-water Algae, 1977). Species:

Similar species --> > C. succisum;

31 μm 63 μm 94 μm; x 640