Genus: Planktonic; colony of 4 (or 2 or 8) cells; cell body crescent in shape, both ends
drawn out as spiny projections; two cells attached each other at the outward mid-region forming "X"-shaped
pairs, two pairs attached at the extreme of the cells;
a single chloroplast plate-like in shape, with two pyrenoids
(Guide book to the "Photomicrographs of the Freshwater Algae", 1998).
Species: Colonies of 4, or 2 or 8 cells, free-floating; cell body crescent in shape, both ends elongated to form a spiny projections, cells attached each other by their convex side; a single chloroplast parietal, plate-like, with large two pyrenoids; cell body 3.5-7 μm wide, 18-28 μm long without spines, spines 20-25 μm long; (Photomicrographs of the Fresh-water Algae, vol. 5, 1986).