Subgenus: Entomum (Apical area deeply indented or notched) Section: Incisa (Cell surface smooth; apical area without spiny projections) Species: Cell body 125-137 μm long, 48-50 μm wide, L/W=2.5, isthmus 19-20 μm wide; (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.4, Shijuhachi-ike (pond), Shiga highland, Yamanouchi town, Nagano Pref., Japan, June 17, 2007 by Y. Tsukii