CHONDRICHTHYES
Chondrichthyes
Chondrichthyes or cartilaginous fishes are jawed fish 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 and Holocephali .The above text is a snippet from Wikipedia: Chondrichthyes
and as such is available under the Creative Commons Attribution/Share-Alike License.