Note 278 — Chapter IX · THE ORDER UNGULATA (continued 4)

These teeth are by some writers classed as canines, as their roots are implanted in the maxillæ; but, as in Rodents, they are originally developed in the gum covering the premaxillæ, in which bones their primitive alveoli are sunk. As growth proceeds, however, firm support for such massive and weighty bodies can only be obtained by their roots gradually sinking through the premaxillæ into the great and specially modified alveolar processes of the maxillæ, but this does not vitiate their homology with the incisors of other mammals.