M.Bravard believes that the whole enormous Pampean deposit is a sub-aerial formation, like sand-dunes: this seems to me to be an untenable doctrine.) Hence we have good evidence that the above enumerated gigantic quadrupeds, more different from those of the present day than the oldest of the tertiary quadrupeds of Europe, lived whilst the sea was peopled with most of its present inhabitants; and we have confirmed that remarkable law so often insisted on by Mr.Lyell, namely, that the "longevity of the species in the mammalia is upon the whole inferior to that of the testacea." (5/3.

"Principles of Geology" volume 4 page 40.) The great size of the bones of the Megatheroid animals, including the Megatherium, Megalonyx, Scelidotherium, and Mylodon, is truly wonderful.

The habits of life of these animals were a complete puzzle to naturalists, until Professor Owen solved the problem with remarkable ingenuity.

(5/4.

This theory was first developed in the "Zoology of the Voyage of the 'Beagle,'" and subsequently in Professor Owen's "Memoir on Mylodon robustus.") The teeth indicate, by their simple structure, that these Megatheroid animals lived on vegetable food, and probably on the leaves and small twigs of trees; their ponderous forms and great strong curved claws seem so little adapted for locomotion, that some eminent naturalists have actually believed that, like the sloths, to which they are intimately related, they subsisted by climbing back downwards on trees, and feeding on the leaves.