longitudinal muscles definition
Earthworm-Muscular System. The earthworm has two muscles which it uses for locomotion, both of which run the whole length of the worm's body. These two muscles are circular muscles and longitudinal muscles (Musurca).The longitudinal muscles are the inner layer of the muscular series and cradle the coelom, the innards of the earthworm (Noble).When the circular muscles are contracted, the diameter of the body is reduced, making the worm thin.hen the longitudinal muscles are contracted, the length of the body is reduced, making the worm short. So, if an earthworm is short and thin, which is a common reaction, both types of their muscles are contracted.