Differential interference contrast (DIC) light micrograph of the body of an Actinosphaerium heliozoan. Heliozoa (sun-animalcules) are unicellular eukaryotic aquatic micro-organisms, classed as protists. They have long stiff arms (actinopodia) radiating from their spherical bodies, which they use to capture their prey and for sensation and movement. Magnification: x150 when printed at 10 centimetres wide at its longest edge.