Crinoids are marine animals that make up the class Crinoidea of the echinoderms (phylum Echinodermata). The name comes from the Greek word krinon, “a lily”, and eidos, “form”. They live in both shallow water and in depths as great as 9,000 meters (30,000 ft). Those crinoids which in their adult form are attached to the sea bottom by a stalk are commonly called sea lilies. The unstalked forms are called feather stars or comatulids. Fossilised crinoid columnal segments extracted from limestone quarried on Lindisfarne, or found washed up along the foreshore, were threaded into necklaces or rosaries, and became known as St. Cuthbert’s beads.