Species: 80-125 μm long, 10-35 μm wide; cylindrical; anterior end a little narrowed and rounded; posterior end drawn out; spiral striae, made up of small knobs; many discoid chloroplasts; two ovoidal paramylon (paramylum) bodies; flagellum about 1/4 the body length; sluggish (Kudo, 1966). 80-180 μm long. Several varieties: var. suprema 140-180 μm, var. marchica, 85-165 micron, var. abruptacuminata, 130-145 μm (How to know the protozoa, 1979). 45-250 μm long, 5-35 μm wide (Illustrated guide, 1985). Cell body 70-96 μm long, 10-14 μm wide, two large paramylon bodies ring-shaped (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).