VOL. L. HO. 592* 



APRIL, 1918 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOTJENAL 

 Devoted to the Advancement of the Biological Science! with 

 Special Beference to the Factors of Evolntion 



Individual Differences and Family Besemblances in 



Hybrids of the Genus Epilobium. 



fessor W. E. Castle 



THE SCIENCE PEESS 

 LANCASTER, PA. GAEEISON, N. T. 



NEWYOEK: SUB-STATIOK 84 



