Genus: Cingulum (horizontal groove) located at the center of the body
(Illustrations of The Japanese Fresh-water Algae, 1977).
Cingulum more or less median; sulcus straight (Illrustrated Guide, 1985).
cell body 50 μm long, 41 μm wide, L/W=,
x 640, a small pond at Kowashimizu, Suwa city, Nagano Pref., Japan, May 21, 2005 by Y. Tsukii
94 μm; x 640