Most comatulids originally have 10 arms, each ray being subdivided once. Comatulids are dioecious, each individual being either male or female. Comatulids consist of 80% calcium carbonate and are unappetising to most predators. Comatulids live on the seabed and on reefs in tropical and temperate waters. Like other echinoderms, comatulids have pentamerous symmetry as adults though the larvae have bilateral symmetry.