VOL. XLV, NO. 535 



JULY, 1911 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOURNAL 

 Devoted to the Advancement of the Biological Science! with 

 Special Reference to the Factors of Evolution 



THE SCIENCE PRESS 

 LANCASTER, PA. GARRISON, N. Y. 



NEW YORK : SUB-STATION 84 



