VOL. XL VI, MO. 446 



JUNE, 1912 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOURNAL 

 Devoted to the Advancement of the Biological Science! with 

 Special Reference to the Factors of Evolution 



Characteristics of Descendants. Dr. J. 



The Inconstancy of Unit Characters. Professor W. E. Castle - 

 Shorter articles and Discussion : Inheritance of Color in the Aleurone Cells 

 of Maize : Professor E. M. East. Nuclear Growth daring Early Develop- 



and Agonti Factors in Mice? A. H. Stcrtevant. The Malthusian Prin- 

 ciple and Natural Selection. Dr. ROSWKIX H. JOHNSON - 



THE SCIENCE PRESS 

 LANCASTER, PA. GARRISON, ff. Y, 



FEW YORK : 8TJB-STATI0H 84 



