Subgenus: Entomum (Apical area deeply indented or notched) Section: Incisa (Cell surface smooth; apical area without spiny projections) Species: Cell body μm long, μm wide, L/W=, isthmus μm wide; (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.5, Tashirodaira marsh, Hakkoda mountain, Aomori city, Aomori Pref., Japan, September 13, 2006 by Y. Tsukii