The habitat and behaviour of Cephalodiscus gracilis (Pterobranchia, Hemichordata) from Bermuda

Cephalodiscus gracilis lives in shallow water around Bermuda. The zooids secrete a transparent coenecium. Several zooids can be attached to a common point. The zooids may be of differing maturity, having from none to five pairs of arms. The mature zooids feed by extending their arms like meridians around a globe with the tentacles of adjacent arms interdigitating to make a spherical filter net. Feeding currents are induced by cilia. The mucus flows along the external surfaces of the arms, around the collar and into the mouth. The rejection current runs on the inside surface of the arms. The rejected material is stored in pellets near the arm tips. It is'flicked'away at intervals.
The larvae are found in densely pigmented stalks attached to the common sucker. The zooids also reproduce by budding.