88 
BAHIA BLANCA 
CHAP. 
the mammalia is upon the whole inferior to that of the 
testacea.” 1 
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 2 solved the problem with remarkable ingenuity. 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. It was 
a bold, not to say preposterous, idea to conceive even ante¬ 
diluvian trees, with branches strong enough to bear animals as 
large as elephants. Professor Owen, with far more probability, 
believes that, instead of climbing on the trees, they pulled the 
branches down to them, and tore up the smaller ones by the 
roots, and so fed on the leaves. The colossal .breadth and 
weight of their hinder quarters, which can hardly be imagined 
without having been seen, become, on this view, of obvious service, 
instead of being an encumbrance : their apparent clumsiness 
disappears. With their great tails and their huge heels firmly 
fixed like a tripod on the ground, they could freely exert the 
full force of their most powerful arms and great claws. Strongly 
rooted, indeed, must that tree have been, which could have 
resisted such force ! The Mylodon, moreover, was furnished 
with a long extensile tongue like that of the giraffe, which, by 
one of those beautiful provisions of nature, thus reaches with 
the aid of its long neck its leafy food. I may remark, that in 
Abyssinia the elephant, according to Bruce, when it cannot 
reach with its proboscis the branches, deeply scores with its 
tusks the trunk of the tree, up and down and all round, till it is 
sufficiently weakened to be broken down. 
The beds including the above fossil remains stand only from 
fifteen to twenty feet above the level of high water ; and hence 
1 Principles of Geologv, vol. iv. p. 40. 
2 This theory was first developed in the Zoology of the Voyage of the Beagle, and 
subsequently in Professor Owen’s Memoir on Mylodon robustus. 
