Genus: Cell body short, with a deep constriction at the center, apical view fusiform or radially symmetrical;
cell apexes without spiny projections; intermediate zone or folded structure appeared during cell division;
zygospores remain within their mother cells
(Illustrations of The Japanese Fresh-water Algae, 1977).
Species: (Photomicrographs of the Freshwater Algae, vol. 1, 1984).