Crinoids (Sea lilies)

Crinoids are marine animals that make up the class Crinoidea, one of the classes of the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. The larvae of crinoids and other echinoderms are bilaterally symmetric but this property is lost during metamorphosis when the adults develop radial symmetry. Those crinoids which in their adult form are attached to the sea bottom by a stalk are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, being members of the largest crinoid order Comatulida.