Genus: Cell solitary; theca usually flask-shaped, of two layers; protoplast with 1 anterior flagellum
encircled laterally by a well-developed collar (Illustrated Guide, 1985).
D. placita: Theca 10 μm long, 4 μm wide; anterior flagellum ~10 μm long (Illustrated Guide, 1985).
Diplosiga Frenzel (Codonosigopsis Senn): With two collars; without lorica; a contractile vacuole; solitary or clustered; fresh water (Kudo, 1966). Transparent; ovoid; on stalk; solitary; with double collar (How to know the protozoa, 1979).