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minuted. If these substances had been roots, then a softer and more succulent 

 kind must have been abundantly produced for the Mylodon, and another coarser 

 kind in still greater abundance for the Megatherium — two hypotheses irreconci- 

 leable with the known history of the uncultivated growth of such roots, and 

 of the animals they serve to sustain in a state of nature at the present day. 

 On the theory that the Megatherioids subsisted on foliage, it is most natural to 

 suppose that the Mylodon and Megalonyx, with teeth most closely resembling 

 those of the Sloths, would feed, like them, on the leaves and tender buds ; while 

 the Megatherium, whose essentially bradypodal teeth were more modified by their 

 arrangement in a closer series, by the nearer approximation of those series to- 

 wards the middle line, by their transversely ridged crowns, and by the great 

 depth of the lower jaw, so as concurrently to offer an obvious resemblance to 

 the Elephant's dentition, would be thereby able to bruise the smaller branches, 

 and to masticate these together with the buds and leaves. 



It is very true that the perfect skeleton of the Mylodon in the Museum of the 

 College confirms the opinion formed by M. Laurillard from the less perfect ske- 

 leton of the Megatherium at Madrid, that the fore-foot of the Megatherium re- 

 sembled that of the great Ant-eater, in so far as regards its equal adaptation for 

 cleaving the soil. But on Baron Cuvier's hypothesis that such was the sole office 

 to which the fore-feet were applied in quest of food, the incongruous proportions 

 and prodigious strength of the posteriors, hind limbs and tail are inexplicable. 

 The founder of Palseontological science has deduced no physiological consequence 

 from the extraordinary expanse of the iliac bones, from the great breadth of the 

 femora, from the strength of the leg or the length of the horizontal base of the 

 above colossal parts. What other office, indeed, could be assigned to these parts 

 of the frame of the Megatherium, on the supposition that the animal subsisted 

 on roots, than that of supporting the body, while one or other, or perhaps both, 

 fore-legs were occupied in digging ? 



Now, if the Megatherium or Mylodon had been constrained, by the nature 

 of their food, to the habitual posture of standing on three legs, the parts 

 to be so supported ought to have been as light as was compatible with 

 their essential offices. There appears no reason why the bony parietes of 

 the abdominal and pelvic cavities should have exceeded the bulk and weight 

 requisite for the support of the contained viscera. Yet both in the Me- 



