Colpodella edax (Klebs, 1893) Simpson and Patterson, 1996. Cells at the front end are pointed or beak-shaped, at the posterior end rounded off, 11-15 microns long and 5-7 microns wide. Flagella inserted subapically. Posterior flagellum somewhat longer than anterior flagellum. Nucleus in the center, contractile vacuole close of the position which the flagella inserted. Predatory on other flagellates.