(sir-ko-moan-ass), gliding flagellates, two flagella insert just below the anterior apex of the cell. The anterior flagellum beats floppily, the posterior flagellum trails against the substrate. Body very flexible and elements may be drawn out as strands behind the moving cells. Common. Lots of species, but the taxonomy is very unstable. This is a compressed cell surrounded by some bacteria. The light circle with the dark centre is the nucleus with central nucleolus, and the very light region is the contractile vacuole. Phase contrast.