How do earthworms feed?
Most earthworms are scavengers that feed on dead organic matter. They feed by passing soil through the gut, from which nourishment is extracted, or by eating organic debris, including leaves accumulated on the surface of the soil. This method of feeding does not require highly developed sense organs (such as eyes, which would be of little use underground) or food-catching structures, and earthworms never possess the often very remarkable and versatile head appendages developed in some of the free-swimming, carnivorous marine polychaete worms. The digestive system is divided into a number of regions, each with a special function. Food that enters the mouth is swallowed by the action of the muscular pharynx, then passes through a narrow esophagus that has three swellings on each side. These are the calciferous glands that excrete calcium carbonate to dispose of excess calcium obtained in the food. The food then moves to the crop, which seems to serve only as a storage organ, and then to
