Chiton

Chitons are marine molluscs of the class Polyplacophora, with about 940 living species and 430 fossil species recognised, also called sea cradles, coat-of-mail shells or, more formally, loricates or polyplacophorans. Their defining feature is a shell of eight separate plates, or valves, that overlap slightly at the front and back edges while articulating well with one another, allowing the animal to flex or even curl into a protective ball when dislodged, with the plates encircled by a skirt called a girdle. The name comes from the Ancient Greek khiton, meaning tunic, and the group has inhabited Earth since the Late Cambrian.