VOL. XIV, NO. S33 



MAY, 1911 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOURNAL 

 Devoted to the Advancement of the Biological Science! with 

 Special Reference to the Factors of Evolntion 



CONTENTS 



l - The Inheritance of Polymorphism and Sex In Colias Philodice. Professor 



John h. Gerould 287 



I- Nucleus and Cytoplasm in Heredity. Professor Michael F. Guyer . 284 



t A Comparative Study of the Structure of the Photogenic Organs of Certain 



American Lampyrida. F. Alex. McDebmott and Chas. G. Crane - 306 



r - Shorter Articles and Discussion : A Neglected Paper on Natural Selection in 



the English Sparrow. Dr. J. Arthur Harris 314 



Notes and Literature : Biometrics, Yule's Introduction to the Theory of Statis- 



THE SCIENCE PRESS 

 LANCASTER, PA. GARRISON, N. T. 



NEW YORK: SUB-STATION 84 



