Delphinide
one of the families into which the order Cetacea is divided.
It comprises such forms as the true dolphins, the fresh-water dolphins of the Ganges and Amazon, the porpoises, the beluga, the orca, and, according to some authors, the narwhal. The members of this group possess considerable diversity in outward form, in skeletal characters, and dentition; and, with the exception of the narwhal they agree in having numerous conical teeth in both jaws. The delphinidæ are found fossil in deposits of Miocene and later date.