Species: Cell body large, 84-105 μm long, 63-74 μm wide, L/W=1.3, isthmus 25-30 μm wide; semicells pyramidal in shape with flattened apex; cellwall covered with large conical projections except the flattened apex; many circular pores present at the center of the semicells (sizes gradually declined from center to margins) (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640