Family: Colorless body; two flagella, one directed anteriorly and the other usually posteriorly; stigma absent.
Genus: Oval, flattened, longitudinally striated; anterior flagellum about four times longer than shorter trailing one; fresh or salt water (How to know the protozoa, 1979).
cell body 16 x 9 μm
ant. flag. 40 μm
post. flag. 25 μm