Muscular System of Sea Urchins
Sea Urchins have a symmetrical body just like any the other species of Echinoderms. Sea urchins have a jaw located toward the center. This place is called the Aristotle's lantern. The mouth contains muscles that surround this place. In other echinoderms, there is an endoskeleton which contains a layer of muscle that helps an animal move its arms and other parts of the body. This is not located in a sea urchin, so they cannot move this way. Sea Urchins also have muscles in reproductive organs.