Cyclidium (sigh-clid-ee-um) is a small scuticociliate, a group which usually has a well developed veil of cilia projecting around the mouth region. This undulating membrane is not extended in the cell in this picture. It eats bacteria. May occur in organically enriched habitats with large numbers of bacteria. Common in freshwater and marine habitats. Pleuronema is a larger member of the same group that is often found in marine habitats. Paracyclidium is similar, but there are no locomotor cilia in the centre of the body whereas it is clear from this image, that the kineties are unbroken. Long caudal cilium. Phase contrast.