Vorticella campanula protozoa, light microscopy. These are ciliate protozoa, so-called because the bell-shaped heads have tiny, hair-like structures (cilia) which are moved in a waving motion to waft food towards them from the surrounding fluid. The cilia can also be used for movement. Each head is attached to a stalk which the vorticella uses to secure itself to an anchor-point. The vorticellae seen here are in an extended position for feeding. When the creature is disturbed it can contract the stalk for protection.