The Seven-armed Seastar Luidia ciliaris, is a rare species found in the Mediterranean Sea. It lives in sandy habitats, from shallow littoral waters down to depths beyond 400m. Its diameter exceeds 40cm. If one or more of its seven long arms is severed for any reason, the seastar has the ability to regrow them. This explains why the arms of some seastars are not all of the same length. Seastars feed on shelled animals such as clams.