1. The Crinoids (Class Crinoidea) The Crinoidea – or Feather Stars and Sea Lilies – are among the most ancient of the Echinoderms

2. Columnal One of the plates that form the stem (stalk) of crinoids (Crinoidea)

3. Crinoids are marine animals belonging to the Phylum Echinodermata and the Class Crinoidea

4. Asteroidea, Blastoidea, and Crinoidea, the Ambulacrum is marked by a deep linear depression, the ambulacral groove.

5. Echinoderms, which are exclusively marine animals, are divided into five classes, the Asteroidea (starfishes), Ophiuroidea (serpent-stars), Echinoidea (sea-urchins, heart-urchins, and sand-dollars), Holothuroidea (sea-cucumbers), and Crinoidea (sea-lilies and feather-stars).