Family: Unicellular or Colonial; cell body spherical, with one or more spiny projections; a single cup-shaped chloroplast with a pyrenoid; asexual reproduction by zoospores or autospores; sexual reproduction by fertilization (Illustrations of The Japanese Fresh-water Algae, 1977).
Genus: Unicellular, but autospore may become temporary colonical; planktonic; cell body spherical with many elongated spiny projections; a single chloroplast cup-shaped, with a single pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998).