Vorticella protozoa. Differential interference contrast micrograph of a Vorticella sp ciliate protozoan. The organism consists of a bell-shaped head and a stalk that is anchored to the substrate. The cilia (tiny hair-like structures) attached to the head are used to capture food and also for movement. Magnification: x570 when printed at 10 centimetres wide.
Credit:&nbsp;FRANK FOX/SCIENCE PHOTO LIBRARY