The Earthworm has two main muscles that run throughout its entire body and help its locomotion. These two muscles are circular and longitudinal muscles. The circular muscles are closest to the epidermis of the worm, while the longitudinal are farther. The longitudinal muscles cradle something called the coelom. The coelom is a fluid filled sack formed from the splitting of lateral plate mesoderm during embryonic movement. The worm is smaller when the circular muscles contract and when it becomes small and thin that means both muscles are contracted. These contractions of the muscles result in a wavy motion that helps the worm to move.
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