Genus: Colony of 4 or 16 cells arranged nearly parallel, within a gelatinous sheath, planktonic; cell body elongated spindle-shaped, slightly curved; a single chloroplast plate-like, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species: Colonies of 4, 8 or 16 cells embedded in a gelatinous matrix; four cells arranging parallel; cell body needle-shaped, 20-60 μm long, 1.5-5 μm wide; (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640