delphinidæ

pl. [Lat. delphin (us)=a dolphin, and fem. adj. pl. suff. -idœ.] 1. Zobl .: 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 po e considerable diversity in outward form, in skeletal characters, and dentition; but in all the head is of moderate size, and, with the exception of the Narwhal, they agree in having numerous conical teeth in both jaws, while nearly all have dorsal fins. 2. Palæont .: The Delphinidse are found fo il in deposits of Miocene and later date, some of the genera being now extinct.