|  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. intermedius ]: Colonies of 2, 4 or 8 cells arranging linearly; cell body elongated ellipsoidal, 11-18 
μm long, 3.5-7 μm wide; terminal cells with 
long spiny projections (10-17 μm long); cell wall smooth 
(Illustrations of The Japanese Fresh-water Algae, 1977).
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