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An illustration of an earthworm. The basic body plan of an earthworm is a tube, the digestive system, within a tube, the muscular outer body. The body is annular, formed of segments that are most specialized in the anterior. Earthworms have a simple circulatory system. They have two main blood vessels that extend through the length of their body: a ventral blood vessel which leads the blood to the posterior end, and a dorsal blood vessel which leads to the anterior end. Most earthworms are decomposers feeding on undecayed leaf and other plant matter, others are more geophagous.

Earthworm

An illustration of an earthworm. The basic body plan of an earthworm is a tube, the digestive system,…

The earthworms are also known as megadriles, in the families Tubificidae, Lumbriculidae, and Enchytraeidae, among others. The basic body plan is a tube, the digestive system, within a tube, the muscular slimy, moist outer body. The body is annular, formed of segments that are most specialized in the anterior and have a simple circulatory system. They have two main blood vessels that extend through the length of their body: a ventral blood vessel which leads the blood to the posterior end, and a dorsal blood vessel which leads to the anterior end. The dorsal vessel is contractile and pumps blood forward, where it is pumped into the ventral vessel by a series of "hearts" (aortic arches) which vary in number in the different taxa.

Earthworm

The earthworms are also known as megadriles, in the families Tubificidae, Lumbriculidae, and Enchytraeidae,…

The earthworms are also known as megadriles, in the families Tubificidae, Lumbriculidae, and Enchytraeidae. Earthworms have a pair of kidneys to every segment, each consisting of a coiled tube wrapped in a mass of small blood vessels, and at its inner end communicating with the body cavity by means of a funnel-shaped opening. Here is a diagram of an earthworm kidney., showing (b) blood vessel, (f) funnel opening into body cavity, (o) outer opening, (s)septum, (w) body wall

Earthworm Anatomy

The earthworms are also known as megadriles, in the families Tubificidae, Lumbriculidae, and Enchytraeidae.…

An illustration of an earthworm escaping a cocoon.

Earthworm Escaping Cocoon

An illustration of an earthworm escaping a cocoon.