Chondrichthyes is a superclass that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. Chondrichthyes are jawed vertebrates with paired fins, paired nares, scales, and a heart with its chambers in series. The superclass has two classes: Elasmobranchii (sharks, rays, skates, and sawfish) and Holocephali (chimaeras). Approximately 940 species.
