Genus: Colonies of 4 (or 2, 8, 16) cells attached side by side, arranged linearly or zigzag; cell body elliptical or spindle or crescent in shape; terminal cells with spiny projections in many species; cell wall usually smooth, but in some species granulated or dented or ridged (Illustrations of The Japanese Fresh-water Algae, 1977). Species (var. longicauda): Cell body 8-10 μm long, 3-4 μm wide; outer cells with longer spiny projections at both ends (10-12 μm long) and at outer sides (5-7 μm long) (Illustrations of The Japanese Fresh-water Algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: a small pond along Prefectural road route 272 (Tsukiyono-Sarugakyo-Onsen-sen), Haba, Minakami town, Gunma Pref., Japan, October 21, 2007 by Y. Tsukii