Family: Similar to Euglenidae in body form and general structure, but without chromatophores (chloroplasts); body highly plastic, although usually elongate spidle.
Genus: Body colorless; plastic; flask-shaped; striated; a funnel-like neck; posterior region stout; a single flagellum protruded from funnel and reaches inward the posterior third of body (Kudo, 1966).
Species: Spindle-form; covered with minute sand-grains; about 58 μm long; fresh water (Kudo, 1966). 50-60 μm long, with attached sand grains (How to know the protozoa, 1979).