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).