The Pharynx

Small prey are usually captured by means of an eversible pharynx(proboscis). The pharynx is rapidly everted and open to enable the jaws to seize the food. Raptorial feeders such as surface-dwelling eunicids, onuphids, glycerids, syllids and nephtyids have long tubular pharynx. When retracted, the pharynx can occupy up to the first 20 segments.

Lying in wait at the burrow these worms use their tiny antennae to detect the surface movements of the prey then slowly move to the burrow opening and seize the prey with the pharynx. The proboscis is everted with an explosive force.

Polychaetes from the family Arenicolidae and Glyceridae use an eversible pharynx or proboscis to punch and anchor themselves in the sediment, then retract to pull themselves forward.
pharynx everted

pharynx retracted

pharynx everted

pharynx everted in Glyceridae

pharynx everted in Phyllodocidae