VON BAER S PRINCIPLE. 



103 



Putting these facts into a table, we have another 

 series : — 



Table of Animals Arranged in the Order of their 

 Appearance upon the Earth. 



This is called the Geologic or Phylogenetic 



Series. 



Now putting these Three Series together, we shall 

 have the following arrangement : — 



We see that there is a complete correspondence in 

 the three series. This is what makes men believe 

 that the higher orders of animals in the history 

 of the earth have been developed from the lower, 

 and that each animal represents in its development 

 (Ontogeny) the history of the race from which 

 it is descended. This last statement is known as 

 voN Baer's Principle. 



