|  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: Colonies surrounded by mucilage; cell body oblong cylindrical with rounded ends, 
6.4-17.5 μm long, 1.7-6.6 μm wide; 
cells arranged in a linear series contacting with about 80% of lateral walls, outer cells slightly convex, 
with short spines on cell pole in two lateral rows, 
inner cells on one side with a longitudinal row of short spines; cell wall smooth 
(Photomicrographs of the Freshwater Algae, vol. 19, 1997).
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