Nassa obsoleta (the little black winkle of the tide flats) devouring a scallop. These little scavengers swarm over the scallop. Occasionally one is active enough to get between the valves, forming a wedge which permits the entrance of others, which quickly consume the scallop. Owing to the alertness of the scallop and its different habitat (Nassa usually being found on the tide flats) little damage is done.