Polychaetes - Feeding and Digestion in Annelids

Polychaetes involve both free moving (errant) and sedentary species. The free moving species are usually macrophagous and the sedentary forms are microphagous. Nereis is an example of a free moving macrophagous polychaete. But Nereis can as well burrow and make use of its proboscis (buccal cavity and pharynx) for this aim. The eversible proboscis is a feeding organ. The pharynx is lined along with hooked jaws and is everted for seizing the prey. The genus Nereis includes species that are carnivorous. Some species of Nereis are omnivorous, feeding on diverse material like algae, invertebrates or detritus on the substratum. Some are scavengers. The tentacles and palps present around the mouth assist in the manipulation of food, besides serving sensory function.