1834.] TYPES OF ORGANIZATION CONSTANT. 17? 



present shells. I was at first much surprised how a large quad- 

 ruped could so lately have subsisted, in lat. 49° 15', on these 

 wretched gravel plains with their stunted vegetation ; but the 

 relationship of the Macrauchenia to the guanaco, now an inha- 

 bitant of the most sterile parts, partly explains this difficulty. 



The relationship, though distant, between the Macrauchenia 

 and the Guanaco, between the Toxodon and the Capybaj-a, — 

 the closer relationship between the many extinct Edentata and 

 the living sloths, ant-eaters, and armadillos, now so eminently 

 characteristic of South American zoology, — and the still closer 

 relationship between the fossil and living species of Ctenomys and 

 Hydrocheerus, are most interesting facts. This relationship is 

 shown wonderfully — as wonderfully as between the fossil and 

 extinct Marsupial animals of Australia — by the great collection 

 lately brought to Europe from the caves of Brazil by MM. Lund 

 and Clausen. In this collection there are extinct species of all 

 the thirty-two genera, excepting four, of the terrestrial quadru- 

 peds now inhabiting the provinces in which the caves occur ; 

 and the extinct species are much more numerous than those now 

 living : there are fossil ant-eaters, armadillos, tapirs, peccaries, 

 guanacos, opossums, and numerous South American gnawers and 

 monkeys, and other animals. This wonderful relationship in the 

 same continent between the dead and the living, will, I do not 

 doubt, hereafter throw more light on the appearance of organic 

 beings on our earth, and their disappearance from it, tlian any 

 other class of facts. 



It is impossible to reflect on the changed state of the American 

 continent without the deepest astonishment. Formerly it mu.st 

 have swarmed with great monsters : now we find mere pigmies, 

 compared with the antecedent, allied races. If BufFon had known 

 of the gigantic sloth and armadillo-like animals, and of the lost 

 Pachydermata, he might have said with a greater semblance of 

 truth that the creative force in America had lost its power, 

 rather than that it had never po.ssessed great vigour. The 

 greater number, if not all, of these extinct quadrupeds lived at 

 a late period, and were tlie contemporaries of most of the exist- 

 ing sea-shells. Since they lived, no ver}^ great change in the form 

 of the land can have taken place. What, then, has exterminated 

 so many species and whole genera ? The mind at first is irre- 



