Biology/Natural History: Feeds on small crustaceans. Eaten by Calliostoma annulatum snail. This animal is a true medusa (jellyfish). It can glide along on the base of the stalk (which is the center of the exumbrella), contract the stalk or fold the calyx of the umbrella. If it becomes detached it clings to the substrate with the tentacles until the disk can reattach. It is not a good swimmer. Spawns in the summer in the San Juans, producing tiny 35 micron eggs. Eggs develop into a creeping, non-ciliated, wormlike larva which settles after a few days and develops its first nematocysts within a week. Juveniles may be able to encyst and overwinter.