Light microscope footage of a group of the ciliate protozoan Paramecium caudatum. This ciliate moves by rhythmically beating its many hair-like cilia. It feeds mainly on bacteria, which it wafts into its mouth. These are digested within temporary digestive vacuoles floating within the cell cytoplasm. The contractile vacuoles act as osmotic regulators, controlling the flow of water across the ciliate's membrane. This ciliate is common in aquatic environments worldwide. Filmed with differential interference contrast illumination. Captured field width: 0.9 millimetres.