A “crinoid” is a marine animal belonging to the class Crinoidea within the phylum Echinodermata. Crinoids are characterized by their cup-shaped body (the calyx) and long, feathery arms that extend from the body and are used for feeding. They are often found in deep-sea environments and can be either attached to the sea floor by a stalk or free-swimming. Crinoids are sometimes referred to as “sea lilies” or “feather stars.” They are considered to be one of the oldest groups of echinoderms, with a fossil record dating back to the Cambrian period.
