Genus: Colonies spherical, with inner empty space; cells attached to each other by a protrusion of cell wall, arranged in a single layer; cell body mostly spherical with some conical or grobular bulges; chloroplasts cup-shaped with a pyrenoid; reproduction by asexual coenobium (Illustrations of The Japanese Fresh-water Algae, 1977). Species: Colonies of 8, 16 or 32 cells, spherical in shape, covered by a mucilaginous envelope; often held in multiple coenobia by the remains of mother cell walls; cells connected to adjacent ones by 5 - 7 long, slender processes; intercellular spaces large; cells up to 24 μm diam. (Photomicrographs of the Freshwater Algae, 1996).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Yakebe-ike (pond), Sayama park, Higashi-Murayama city, Tokyo, Japan, February 11, 2006 by Y. Tsukii