Lagenorhynchus

a genus of dolphins of the suborder Odontoceti (toothed whales). The body measures from 1.8 to 3 m long. The head is foreshortened. The beak is short and poorly demarcated from the frontal-nasal cushion. The upper and lower edges of the caudal stem are high and in the shape of a crest. The dorsal fin is sickle-shaped and deeply notched. The animal has between 90 and 160 teeth. Most species are black and white in color.

There are six species, three of which are found in the waters of the USSR: the white-sided dolphin (L. acutus) and white-beaked dolphin {L. albirostris), which live in the North Atlantic, and the Pacific white-sided dolphin (L. obliquidens), which is found in the North Pacific.