Species: Cell body slightly large, (62-87)-100 μm long, (45-70)-74 μm wide, isthmus 37-53 μm wide, L/W=1.3; semicells elliptial, apex broadly rounded, slightly flattened, apical view circular or broad ellipitical; cell wall covered with small pores interspersed with many dots, (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Maimeno-ike (pond), Norikura highland, Azumi, Matsumoto city (formerly Azumi village), Nagano Pref., Japan, June 8, 2006 by Y. Tsukii