Species: 65-112 μm long, 15-30 μm wide; cylindrical; highly plastic; numerous elongate (?) chloroplasts; paramylon (paramylum) bodies discoid (Kudo, 1966). Cell body fusiform, 58-80 x 22-30 μm, anterior rounded, posterior tapered into a short process, chloroplasts deeply lobed and forming chromatophore bands, 6-11 in numbers, each containing a large pyrenoid covered on both sides by a watchglass-shaped sheath of paramylon, nucleus spherical 13 μm in diam., flagellum 1-1.5 body length, stigma (eyespot) 5-6 μm in diam., muciferous bodies spindle-shaped, lying side by side in helical rows, paramylon granules elliptical (Phtomicrog. Freshw. Alg. 14: 26, 1995). Cell body spindle-shaped, posterior pointed, euglenoid movement rare, 62-85 μm long, 17-24 μm wide (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).

31 μm 63 μm 94 μm; x 640

Euglena sociabilis ??, cell body μm long, μm wide, x 640, Doman-green Park, Nishi-Urawa, Saitama Pref., Japan, February 2003 by Y. Tsukii
31 μm 63 μm 94 μm; x 640