* T. volvocina Ehrenberg var. volvocina: lorica 10-20 μm long (How to know the protozoa, 1979). Lorica spherical, no collar, smooth; 16-20 μm diam. (Illustrations of The Japanese Fresh-water Algae, 1977).
Trachelomonas volvocina Ehrenberg var. derephora Conrad: Lorica with short collar; 10-11 μm diam. (Illustrations of The Japanese Fresh-water Algae, 1977).