TOL. XLVn, NO. 556 



APRIL, 1913 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOURNAL 

 Devoted to the Advancement of the Biological Seiencei } 

 Special Reference to the Factors of Evolution 



t Case, with Some Cut 



THE SCIENCE PRESS 

 LANCASTER, PA. GARRISON, V, ¥. 



NEW YORK : SUB-STATION 84 



