When feeding, a zooid of Cephalodiscus is perched at the mouth of the tube or out on one of the spines, using the cephalic shield as an adhesive disc. All its arms are arched to form a basket.The picture shows ciliary currents of Cephalodiscus zooid. Curved arrows indicate water moving toward arms and tentacles and into rejection current. Upward-pointing arrows represent rejection current in center of lophophore. Arrowheads show food canal behind oral lamella. Arrows on trunk and stalk indicate patterns of particle movement on ciliated epidermis.
The methods of water movement and particle clearence during feeding in Cephalodiscus similarly occur in bryozoans, phoronids, brachiopods, and other pterobranchs.
Source:
Lester, S.M. 1985. Cephalodiscus sp. (Hemichordata: Pterobranchia): Observations of functional morphology, behaviour and occurence in shallow water around Bermuda. - Marine Biology 85, 263-268.
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