Crinoidea (Gr. a lily, and shape), animals in shape like a water lily, consisting of an expanded or spreading disk or closed bud, upon the end of a long, slender, jointed calcareous stem. The name was given by J. S. Miller, author of the "Natural History of the Crinoidea, or Lily-shaped Animals." They constitute an extinct family of echinoderms of the radiated division of animals, and in the forms of the encrinite and pentacrinite were wonderfully abundant in the limestones of the Silurian period. Their remains now constitute the great portion of the material of strata which extend over large districts, and are several feet thick. Living representatives of the stemmed crinoids are the pentacrinus caput-medusae of the West Indies, and the rhizocrinus of the deep sea off the coast of Norway.