The Polyplacophora or chitons are a small class consisting entirely of marine species.
Chitons are marine molluscs which are highly adapted to life in the intertidal zone.
They may be found on most rocky shores and two species, Lepidochiton cinereus and Lepidopleurus asellus are common around the British Isles. Chitons range in size from 1-2cm in Lepidochiton to over 30cm in the Pacific species Cryptochiton . The shells of chitons are characteristically divided into 8 transverse, overlapping shell plates or valves. The foot is greatly expanded, forming a large flattened sole which is used not only for locomotion but also for maintaining firm contact with the rock surface. Chitons feed on small particles of algae on the rock surface which are scraped off using the radula.