A classic, Lumbricus Terrestris, better known as the Earthwom is a common everyday worm that lives in most tropical, or subtropical environments. The Earthworm can have varying length which varies largely based on the environment that it is living in. These facts can be the weather conditions, type of soil that the worm lives in, and the amount of nutrients that the worm is consuming. The Earthworm can grow anywhere from 10mm to 3m long! The Earthworm's circulatory system is a closed circulatory system with blood vessels, and five hearts. To clean blood however, the Earthworm does not have kidneys, but nephridia, which serves the exact same purpose