Crinoids (Sea Lilies and Feather Stars)

Crinoids, the sea lilies and feather stars, are neither abundant nor familiar today, yet they dominated the Paleozoic fossil record of echinoderms and shallow marine habitats until the Permo-Triassic extinction nearly wiped them out. Stalked crinoids, the sea lilies, lived attached to the bottom and filtered food particles from passing currents, and the living ones mostly inhabit deep water. Living crinoids are the only remaining attached suspension-feeding echinoderms. An unstalked comatulid, or feather star, superficially resembles a starfish but has its mouth facing up and crawls by walking on specialized structures called cirri.