Coloured scanning electron micrograph (SEM) of Theocapsa sp. radiolarian. Radiolaria are single-celled protozoans that are found in marine plankton. They have a silicate skeleton with pores through which pseudopodia (false feet, not seen) of protoplasm project. As the animal floats in ocean currents the pseudopodia trap food particles on which the radiolarian feeds. This specimen was obtained from a Deep Sea probe taken in the Southern Atlantic Ocean by AWI Bremerhaven. Magnification: x550 when printed at 15 centimetres wide.