Molluscs have a mantle that secretes the calcium carbonate that makes up the shell.
They inhabitat numerous different environments with a large number living in the sea. Octopuses and squids have evolved to intelligent mobile forms with complex behaviour. The commonest and most widespread chiton found on British rocky shores is Lepidochitona cinerea . On many shores it is the only species to be found. It is in this class of animals that the typical spiral snail-like molluscs are classified.