Cycliophora is a small and recently discovered phylum of symbiotic animals that live on the mouthparts of lobsters. They were first described in the late 1990s and are one of the smallest and least well-known animal phyla. Cycliophorans are characterized by their small size (less than 0.5 millimeters long) and the presence of a distinctive ring of cilia that surrounds the mouth. They feed on bacteria and other small particles and are believed to play a role in maintaining the health of the lobster's mouthparts. To date, only two species of Cycliophora have been described, and much remains to be learned about the biology and evolution of this unusual group of animals.