VOL. XIV, NO. 534 



JUNE, 1911 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOURNAL 

 Devoted to the Advancement of the Biological Scieneei with 

 Special Reference to the Factors of Evolution 



CONTENTS 



2 



Inheritance of Fecundity in the Domestic Fowl. - Dr. Raymond Pearl. 

 The Biometric Proof of the Pure Line Theory. - Dr. J. Arthur Harris. 

 The Influence of Changed External Conditions on the Development of Two 



Species of Moths. - - - Professor Thomas H. Montgomery 

 Shorter Articles and Discussion: The Ontogeny of a Genus. Austin Hob art 



Clark 



THE SCIENCE PRESS 

 LANCASTER, PA. GARRISON, H. T. 



NEW YORK: SUB-STATION 84 



