Antarctic Ocean and South Seas.

North Pacific and West Arctic Ocean.

Order CETACEA.

Teeth all similar, conical, sometimes not developed. Palate often furnished with transverse plates of baleen or whalebone. Body fish-shaped, smooth, bald. Limbs clawless; fore limbs fin-shaped; hinder united, forming a forked horizontal fin. Nostrils enlarged into blowers. Teats two, inguinal.—Carnivorous.

They may be divided by the form of the pectoral fin, thus:—

I. Pectoral fin broad, truncated or rounded at the end; fingers 5, shorter than the arm-bones, subequal, gradually shorter in the series.—Balænidæ, Catodontidæ, Susoidea, Orcadæ, Belugidæ, Pontoporiadæ, Hyperoodontidæ, Epiodontidæ, Ziphiidæ.

II. Pectoral fin elongate, obliquely truncated on the inner side; fingers 5, elongate, longer than the arm-bones, the second and third much longer than the rest.—Iniidæ, Delphinidæ, Grampidæ, Globiocephalidæ.