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.6, a marsh pond at Sensho-ga-hara, near Akita-komagadake (mountain), Shizukuishi town, Iwate Pref., Japan, August 6, 2007 by Y. Tsukii