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).
50 μm
100 μm
150 μm; x 400 :
31 μm
63 μm
94 μm; x 640
Cosmarium, x 400, x 640, Uruguay Nov. 1999, photo by Yuuji Tsukii
