ABSTRACT

Investigations on the feeding behaviour of Antedon bifida were done using a coloured suspension of food particles. Scanning electron microscope-observations were performed on pieces of comatulid arm or calyx, fixed in Bouin’s fluid for a 12 hour period. The feeding system of adult A. bifida consists of ciliated grooves, lined by well-developed feeding appendages or podia bearing conspicuous papillae. Specialized feeding units, i.e. triplets of unequal-sized podia with an associated protective lappet occur all along the pinnular grooves. Both the primary and secondary podia of the feeding units are food-collecting appendages. Food particles are trapped on the mucus secretion of the podal papillae. Particles are transferred to the ciliary tracts of the grooves by the wiping action of collecting podia against the ciliary current. Adult and larval feeding units are rather similar, being both made of collecting podia, paddling podia, protective structures (lappets or larval oral plates) and biliary tracts.