Subgenus: Entomum (Apical area deeply indented or notched) Section: Incisa (Cell surface smooth; apical area without spiny projections) Species: Cell body 47-73 μm long, 34-36 μm wide, isthmus 11-14 μm wide (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Utsubo-numa (a pond), Zao mountain, Zao onsen, Yamagata city, Yamagata Pref., Japan, July 13, 2008 by Y. Tsukii