Genus: Colony of two cells, planktonic; cell body ellipsoidal, both ends rounded; two cells attached side by side; cell wall smooth, covered thin spiny projections; each projection swell at the base; two chloroplasts plate-like in shape, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species:

31 μm 63 μm 94 μm; x 640