PHYLOGENY OF VERTEBEATES, 193 



the individual history of human development, we have 

 already recognized the undeniable fact that, in developing out 

 of the egg, man at first does not differ from other Vertebrate 

 animals, and especially from Mammals, we must necessarily 

 come to the conclusion, in regard to the palseontological 

 history of his development, that man has, historically, 

 actually developed out of the lower Vertebrata, and that he 

 is directly derived from lower Mammals. This circumstance, 

 together with the many high interests which, in other 

 respects, entitle the Vertebrata to more consideration than 

 other organisms, justifies us in examining the pedigree of 

 the Vertebrata and its expression in the natural system, 

 with special care. 



Fortunately, the records of creation, which must in all 

 cases be our guide in establishing pedigrees, are especially 

 complete in this important animal tribe, from which our 

 own race has arisen. Even at the beginning of our century 

 Cuvier's comparative anatomy and palaeontology, and Bar's 

 ontogeny of the Vertebrate animals, had brought us to a 

 hish level of accurate knowledge on this matter. Since 

 then it is especially due to Johannes Miiller's and Rathke's 

 investigations in comparative anatomy, and most recently 

 to those of Gegenbaur and Huxley, that our knowledge 

 of the natural relationships among the different groups of 

 Vertebrata has become enlarged. It is especially Gegen- 

 baur's classical works, penetrated as they are throughout 

 with the fundamental principles of the Theory of Descent, 

 which have demonstrated that the material of comparative 

 anatomy receives its true importance and value only by the 

 application of the Theory of Descent, and this in the case 

 of aU animals, but especially in that in the Vertebrate tribe. 



VOL. II. O 



