Class

• Echinoidea

  Sea urchins and sand dollars.

• Crinoidea

  Sea lilies.

• Ophiuroidea

  Brittle stars and basket stars.

• Holothuroidea

  Class of echinoderms including the sea cucumbers.

• Asteroidea

  Sea stars.

Also contains

• echinoderm

  Marine invertebrates with tube feet and five-part radially symmetrical bodies.