Chondrichthyes, class Chondrichthyes - cartilaginous fishes

holocephalan - fish with high compressed head and a body tapering off into a long tail

elasmobranch, selachian - any of numerous fishes of the class Chondrichthyes characterized by a cartilaginous skeleton and placoid scales: sharks; rays; skates

fish - any of various mostly cold-blooded aquatic vertebrates usually having scales and breathing through gills; "the shark is a large fish"; "in the livingroom there was a tank of colorful fish"