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: Cell body 20-26 μm long, 14-27 μm wide, L/W=1, outline shape transversely rectangular, apical angles form a connecting process with adjacent cells, which makes elliptic excavation between adjacent cells; vertically triangular, sides slightly convex and angles rounded; filaments untwisted (Photomicrographs of the Freshwater Algae, vol. 1, 1984).

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640