Features a prominent, fan-shaped radiolar crown composed of feather-like filaments used for feeding and respiration. The worm’s body is elongated and soft, housed within a tough, parchment-like tube that it secretes. Commonly inhabits coral reefs, rocky substrates, and sandy bottoms, where it attaches its tube to hard surfaces. A filter feeder, it uses its radiolar crown to capture plankton and organic particles from the water column. The filaments are covered in cilia that transport food to the mouth.