These skittish little worms will instantaneously retract their gill plumes into a calcareous tube following a shadow or other disturbance. The funnel-shaped operculum then blocks the tube's entrance. Gill plumes about 10 mm. Depth 10m.
Should one suddenly approach these tube worms, they will suddenly retract into their tubes. As you might guess, these tightly packed worms clone. The tiny tubes measure less than 1 mm in diameter.