Polarised light micrograph of a Phacus sp. euglenoid protozoan. It is flat and leaf-shaped, with a rigid cytoskeleton known as a pellicle. It has a flagellum that is as long as its body, which it undulates for locomotion. A small, single eye spot (red) allows it to move towards light. Phacus are commonly found in freshwater habitats around the world. Magnification: 372x when printed 10 centimetres wide.