BULLETIN Of THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 24. PP. 283-292 JUNE 11, 1913 



PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



CERTAIN THEORETICAL CONSIDERATIONS AFFECTING 

 PHYLOGENY AND CORRELATION 1 



BY W. D. MATTHEW 



(Read before the Paleontological Society December SO, 1912) 



CONTENTS 



Page 



Theory of centers of dispersal 283 



Admixture of blood through migrations 284 



The English race as an illustration 284 



Applicability of the principle to animals 285 



Effect of interrupted migrations ; 287 



Effect of remoteness from dispersal center 287 



True nature of a phyletic series 288 



Correlation of homotaxial stages of a phylum 288 



Correlation of Cenozoic mammal fauna? 290 



The Pampean fauna : Equidre and ground sloths 291 



Theory of Centers of Dispersal 



In a former communication to the Society 2 I discussed the evidence 

 for the continuity of evolution from the standpoint of vertebrate paleon- 

 tology. The theory adopted to interpret the evidence was that of evolu- 

 tion of each race in a center of dispersal, and spread from there in suc- 

 cessive waves of migration to other regions. The present contribution 

 aims to discuss certain phases of this theory in their effect on the struc- 

 ture and affinities of a phyletic series in a region remote from the center 

 of dispersal. 



The considerations to be presented and their effects on the composition 

 and affinities of a race are familiar to modern ethnologists. They arc 

 recognized facts of the dispersal of the human races, and their effect on 

 the affinities of each race is clearly seen and universally recognized. 



1 Manuscript received by the Secretary of the Paleontological Society January 28, 

 1918. 

 -Continuity of development. Popular Science Monthly, Nov., 1910. 



XX Bull. Geol. Soc. Am., Vol. 24, 1912 (288) 



