What is the function of esophagus in an earthworm?

Answer 1

The esophagus of an earthworm is part of the earthworm's digestive tract, between the pharynx and the crop, and it basically just moves the earthworm's food from the pharynx to the crop. It also helps to keep the food from backing up (making the worm barf/throw up).

Answer 2

Prostomium Some species of earthworms have a tongue-like lobe above the mouth called prostomium. The prostomium is actually a sensory device. Earthworms do not have a nose, eyes, ears, or hands to gather sensory information about their environment. Instead, they depend on their prostomium and sensory receptors in their skin to "feel" their way through the soil. The peristomium is the first segment from the mouth.