Cell body flat, anterior narrowed, posterior broadly rounded, with short blunt cauda,
30-40 μm long,
20-30 μm wide, cauda usually straight, but
rarely slightly curved, dorsal furrow short and shallow, lateral margins broadly rounded or nearly straight,
periplasts longitudinally striated, usually a single large paramylon body but sometimes accompanied with a second
smaller one (Photomicrograph of the freshwater algae, 3: 71, 1985).
Cell body 23-40 μm long, 20-30 μm wide,
dorsal view nearly spherical; cauda short V-shaped and slightly curved or straight, striae also straight;
a locomotive flagellum nearly the same as the cell body in length;
paramylon bodies disc-shaped with a hole at the center, 1-2 in number;
(An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).
Phacus curvicauda Swirenko: Cell body 24-26 μm diam., (25)-38-30 μm long; 2 paramylons (Illustrations of The Japanese Fresh-water Algae, 1977).