Species (var. minima Mainx, 1927):
Cell body spidle in shape, 29-42 μm long, 11-17 μm wide,
euglenoid movement rare, 3-6 (rarely 7) chloroplasts saucer-shaped or rectangular with wavy margin,
a pyrenoid covered with paramylon sheath located at the center,
a locomotive flagellum nearly the same length as the cell body,
nucleus spherical, 8 μm in diam., stigma (eye spot) 3 μm
(An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).