Anchored in place by their feet, two rotifers feed by beating the cilia that line their coronas and which are used to draw in bacteria and tiny protozoa. The beating organ in each of their 'throats' is the mastax, which is used to grind up food. Rotifers are common multicellular organisms found in pond water and help form the base of the food chain. They also serve important roles as decomposers in the environment and in waste water treatment. The one featured here measures about 300 microns in length and was recorded under Nomarksi DIC illumination.