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).
Species:
Vegetative cells spherical, 8-10 μm diam.,
with short spines 20-40 μm long,
1 chloroplast cup-shaped, 1 pyrenoid
(Illustrations of The Japanese Fresh-water Algae, 1977).