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217 



CHAPTER XXXI. 



EDENTATA EXTINCT SPECIES DATE AND RANGE OF MEGATHEROID SPECIES IN NORTH AMERICA 



EXISTING SPECIES. 



Edentata. (Maps 58 and 59.) — Although the fauna of most countries is clistingiiished by- 

 some element which it possesses in a greater degree than any other, and which gives it its 

 peculiar character, none of them enjoy absolute and sole possession of the special forms which 

 give the fauna their character. Thus Africa is the land of the Antelopes and heavy pachyderms, 

 Australia that of the Marsupials, and South America of the Edentata ; but Africa has to share 

 the Pachyderms and Antelopes with India ; Australia, the Marsupials with South America ; and 

 the Edentata of America are represented (although but feebly) in Africa and India. 



There is considerable resemblance between South America and Australia in the past history and 

 in the present conditions under which their special fauna exists. In both it has flourished in 

 greater vigour than it now does ; in both the Carnivora are feebly represented — both have some 

 typical forms in common ; and in both the place of the feeble and small animals which now 

 inhabit them was filled by gigantic animals allied in structure but strange in form, which puzzle 

 us as to their appearance and the means bj^ which they gained their living. Nature has framed 

 strange fellows in her time, but none of them stranger than some of the Edentata. 



The Edentate fauna of South America is one of the instances which is most frequently brought 

 forward in illustration and support of the view, that each country has a special fauna, due to some 

 general law, which has been in operation through past ages as well as now, in some mysterious way 

 suiting the animals to their abiding place, and preventing them wandering into other bounds. I 

 have already shown how I think the law of change origmating new species explains this. That 

 species do not pass the limits of their special range, except when driven, is, in the first place, due 

 to their being most comfortable where they are, and consequently indisposed to leave their present 

 quarters, and in the next place, when driven beyond their bounds, either by geological changes or 

 insufficient food for their numbers, the change of condition alters them into new species, so that, 

 although they are virtually the old creatures in new lands, they are not recognisable. 



The further back we go in the history of the globe these influences must have had less and less 

 effect. The conditions of life were then everywhere more uniform, and the passage from one 

 I^art of it to another entailed little alteration in the circumstances of the animal. Hence the rarity 

 of change of form and of new species. In those long gone-by times, too, pro%ances may have 

 retained their specialty from another cause, neither more nor less than the law which keeps the 

 prisoner in his dungeon, and the bird in its cage. " I can't get out," may have been with them 

 the sole cause of their then staying where they were. 



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