Genus: Body round to polygonal; cingulum median, deep; thecal plates 5-6 in cingulum; some with apical and antapical horn (Illustrated Guide, 1985). Epicone (or epitheca) consists of 11-14 thecal plates; hypocone (or hypotheca) of 7-8 thecal plates (Illustrations of The Japanese Fresh-water Algae, 1977). Species:

31 μm 63 μm 94 μm; x 640