CHAPTER II 



EVIDENCES OF EVOLUTION FROM ANATOIVHST, 

 EMBRYOLOGIST AND PHYSIOLOGIST 



Three Foundations of the Doctrine of Descent — Ho- 

 mologies — New Organs from Old — Classification — Vestigial 

 Structures — The Recapitulation Doctrine. Experi- 

 mental Evolution — Direct Evidence of Blood-relation- 

 ship — Man as Transformist. 



Three Foundations of the Doctrine of 

 Descent. — The general theory of organic 

 evolution — for so long conveniently called 

 the "doctrine of descent" — has a tripod 

 basis. 



(a) It rests, as we have seen, on definitely 

 ''historical" evidence — on what can be ac- 

 tually proved in regard to ancestry. Thus 

 recent discoveries have made the lineage of 

 the elephant convincingly clear, equalling, if 

 not surpassing, in evidential value that of 

 the horse itself. 



(b) It rests also upon anatomical evidence, 

 on the disclosure of structural resemblances, 

 often beneath a mask of functional differ- 

 ences, which are in many cases so intimate, 

 so thoroughgoing, so detailed, that it is im- 

 possible to doubt that they spell affiliation. 



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