A mong the best known of all the bivalves, scallops have fan-shaped shells, with unequally size "ears" on either side of the umbones.___*____ The internal ligament occupies a triangular pit below the umbones. The hinge is toothless when adult. There is a single, Large muscle scar at the center of each valve (the site of the muscle is eaten as a delicacy). Young scallops usually attach themselves to hard objects with their byssus. There are many species found worldwide.