|MadSci Network: Zoology|
Yes. Earthworms have several hearts. Earthworms have dorsal and ventral blood vessels. At the front of the worm are several very muscular arches of the circulatory system that actually pump the blood from the dorsal vessel to the ventral vessel. After the blood is pumped into the ventral vessel, it is pumped to the rest of the worm. Some of the blood is pumped through arches directly under the skin where it absorbs oxygen. After the blood is oxygenated, it returns to the dorsal vessel. The hearts that pump the blood are more like arteries that expand and contract, pushing blood in the proper direction. They are the simplest type of heart.
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