sharks and rays are examples of what kind of fishes
Chondrichthyes (/ kɒnˈdrɪkθiiːz /; from Greek χονδρ-chondr-' cartilage', ἰχθύς ichthys' fish') is a class that contains the cartilaginous fishes: they are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone. The class is divided into two subclasses: Elasmobranchii (sharks, rays, skates, and sawfish) and Holocephali (chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class).