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gatherium and Mylodon, those bones, as the sacrum, ilia and ischia, which take 

 least share in that office, assume proportions which, compared with those in the 

 large grazing Herbivora, are gigantic and monstrous. And if these bones had 

 not been otherwise concerned in the acquisition of food, than in being adequately 

 propped up during the operation, their enormous development loses every other 

 significance than as the condition of a concurrent, and otherwise unintelligible, 

 massiveness of the hind-legs and tail. 



Such colossal proportions both of the parts supporting and those supported, 

 can only be explained teleologically, on the hypothesis which requires them as 

 the conditions of strength adequate to the habitual acquisition of food by uproot- 

 ing trees. Such actions — the same amount and combination of muscular forces 

 — have ceased to be manifested by terrestrial quadrupeds in the existing creation, 

 and seem impossible under any other conceivable modifications of the mam- 

 malian type than those which characterized the extinct race of Megatherians. 

 In the task of thinning the American forests the brute force of the Mylodon has 

 been superseded by the axe of the Backwood's-man. 



Thus, then, in reference to the comparative probability of the fossorial, the 

 chmbing, and the uprooting hypotheses of the living Megatherians, it has been 

 shown that the most characteristic modifications of the bony framework of these 

 extinct animals are left unexplained by the first, that they directly oppose them- 

 selves to the second, and become intelligible only under the third view, which is 

 that propounded in the present Memoir : it may also be added, that this is the 

 only theory of the Megatherians which does not require the postulate of a different 

 condition of the vegetable knigdom from that which now prevails. 



The Cuvierian view, which assumes at the outset a kind of food not in- 

 dicated by the teeth, and condemns the colossal creature to dig for each morsel, 

 and so to the endless repetition of a task now assigned only to diminutive 

 quadrupeds, at the same time requires for the support of the generations of the 

 Megatherian race an abundance of esculent roots in a state of nature equal to 

 that now raised on the best-cultivated and most fertile soils. 



Dr. Lund, with a truer insight into the nature of the food of the Megatherioid 

 animals, confesses that the scansorial hypothesis is untenable, without assuming 

 the former existence of trees as much surpassing in size those of the present day, 

 as the Megatherium exceeds the Sloth. 



