The lateral line, together with the ampullae of Lorenzini comprise the electrosensory component of the sharks sensory system.  The lateral line allows the shark to orient to particle movement or sound.  It consists of structures called neuromasts which are located in canals that lie just below the surface of the skin or the scales.  Similar to the ampullae of Lorenzini there are pores that open to the outside and movement caused by prey can be detcted by the neuromasts.