Drawing of upper and lower teeth of a shark of genus Lamna (porbeagles).
Date published 1911
Source Encyclopædia Britannica, 11th ed., Vol. 24, p. 807
Author Albert Charles Lewis Gotthilf Guenther; John Graham Kerr
Source: https://commons.wikimedia.org/wiki/File:Britannica_Shark_Lamna_Teeth.png

The porbeagle or porbeagle shark (Lamna nasus) is a species of mackerel shark in the family Lamnidae, distributed widely in the cold and temperate marine waters of the North Atlantic and Southern Hemisphere.