Family: Small, less than 50 μm;
oblong to ovate; ridges faint or absent.
Genus: Body ovate in locomotion; longer than broad; with more or less thick clear zone around granular mass; uninucleate (Illustrated Guide, 1985).
Species: 30-35 μm; similar to D. guttula; slow moving (How to know the protozoa, 1979). Clear ectoplasm around cell body.
Images of collecting locality:
No. 1, Oyumi-ike (a pond), Chuo-ku, Chiba City, Chiba Pref., Japan, December 24, 2007 by Y. Tsukii