MAMMALIA. 13 



rupeds must have acknowledged him as the head of the Animal Kingdom. To 

 the tongue of a Giraffe and the proboscis of a Tapir, there was added the power 

 of rotatino- the bones of the forearm. These prehensile organs were suited to a 

 leaf-feeder. That the animal was not carnivorous, is settled by the structure of 

 its molar teeth : it lacks incisors ; therefore it was not a Ruminant. But if the 

 great animal fed on foliage, how did it obtain it ? The Elephant gathers its food 

 with a long proboscis. The "Giraffe, standing on stilt-like forelegs, and reaching 

 out its attenuated neck, plucks the high branches with long flexible lips and 

 muscular tongue. The Megatherium could imitate neither. Did it climb like 

 the Sloth? Such was the conjecture of the Danish Naturalist, Dr. Ltjnd ; but 

 the clumsy make and the immense bulk and weight of the creature forbid it. 

 The structure of the forefeet, moreover, militates against the theory ; for the 

 outer digit is hoof-like, as if made for terrestrial progression. The hindlegs, too, 

 are much shorter than the forelegs ; and the tail is too short and thick for pre- 

 hensible purposes. 



The fossorial hypothesis, too, has no better foundation than the scansorial. 

 In burrowing animals, as the Mole, the pelvis is remarkably slender, and the 

 claws form a continuous plane with the palm of the foot ; while in the Mega- 

 therium the pelvis is remarkably large, and not one of the claws can be brought 

 into a line with the metacarpus. The fore-arms were plainly formed for grasping, 

 not climbing or digging : they were instruments of tremendous strength, evi- 

 dence of which is furnished by the deep grooves and sharp ridges on the radius 

 and ulna, the starting points of stout tendons and muscles. The moment we 

 estimate this force, the colossal proportions of the hind-extremities lose their 

 anomaly and harmonize with the front. The application of the fore-arms to the 

 work of tearing down a tree would demand a corresponding fulcrum, such as we 

 find in the heavy pelvis, the ponderous tail and the massive hind-legs. 



The Megatherium needed not agility for securing prey, for it was not carniv- 

 orous ; nor for flight, for its size alone must have been a protection against any 

 living foe. Had we beheld it living on its native plains, its slow movement 

 would have excited our wonder as much as its bulk. It was doubtless a solitary 

 animal. The gathering together in herds was not required for self-defence : 

 indeed, the necessities of the creature to obtain an enormous daily supply of food 

 would not have allowed it, unless the vegetation of that day were far more dense 

 than is the modern vegetation of the same region. When stripping the trees it 

 had prostrated, its position was probably a reclining one ; and Professor Agassiz 

 has ventured the opinion that this crouching attitude was constant to the ani- 

 mal, and that it crept along with the full length of its fore-arm resting upon the 

 ground. 



The Pampas, where the remains of the great fossil have been chiefly found, 

 are vast plains, stretching from the mountains of Brazil to Tierra del Fuego. 

 Palms grow at one end, while snow covers the other almost the entire year. The 

 soil is chiefly a dull-reddish, slightly-indurated, argillaceous earth, with here and 

 there calcareous concretions ; underneath are beds of stratified gravel and conglo- 

 merate. These deposits constitute the Pampean formation, which varies in depth 

 from twenty to one hundred feet. They were slowly formed at a time when the 

 Atlantic reached far westward to the foot of the central mountain chain, down 

 whose flanks the rivers brought the detritus and spread it beneath the waters in 

 level layers at some distance from the shore. Carcases of animals floated down 



