110 ARMADILLOS AND AARD-VARKS. 



other allied extinct forms ranging throughout America, 

 which in some respects serve to connect the sloths with 

 the anteaters. This marked restriction of the existing 

 edentates in the southern hemisphere, and their especial 

 abundance in South America, at once stamps them as a 

 very lowly group of animals, there being a well-marked 

 tendency for the preservation of the humbler forms of life 

 in the southern continents and islands of the globe. There 

 is, indeed, a question whether the pangolins, and more 

 especially the aard-varks of the Old World, have any real 

 kinship with the more typical American edentates, but 

 apart from this possibility of the artificial nature of the 

 group as at present constituted there can be no doubt but 

 that all its members are what may be called degraded 

 types that is to say, that instead of having advanced in 

 the struggle for existence they have lost some of the 

 attributes of the higher animals ; evidence of this degrada- 

 tion being afforded by the indications above mentioned of 

 their having been formerly provided with two sets of teeth. 

 In saying that the edentates are lowly and degraded 

 examples of the mammalian type we by no means intend, 

 however, to imply that they are not admirably adapted to 

 their own particular modes of life, or that they have not 

 developed special structures unknown among the higher 

 mammals. In truth, precisely the contrary is the case, 

 since these creatures have taken to modes of life unlike 

 those of the majority of the larger mammals, and have 

 more or less specially modified their structure in accordance 

 with such peculiar habits, so that they are thoroughly and 

 perfectly suited to their environment. And we may add 

 that it is doubtless due to these peculiarities of structure 

 and habits that they have been enabled to survive and 

 hold their own against the competition of the higher 

 forms. 



Thus, Jfi the first place, with the exception of a few 

 armadillos, the whole of the edentates are strictly noc- 

 turnal ; and while the sloths spend the whole of their lives 

 among the branches of the dense forests of South America, 

 some of the others have taken to a burrowing subterranean 

 life. Moreover, the armadillos and the pangolins have 



