Th 



e 



Journal of Heredity 



(Formerly the American Breeders' Magazine) 



Vol. VI, No. 1 January, 1915 



CONTENTS 



Sexuality in Plants, by Duncan S. Johnson 3 



Prepotency, by Edward N. Wentworth ^ 17 



Origin of Shetland Ponies, by J. Cossar Ewart 20 



Live-Stock Genetics, a Report by the Research Committee on Animal 



Breeding 21 



Eugenics Congress Postponed 31 



The Determination of Sex, by Leonard Doncaster 31 



Feeblemindedness, a review by the Editor 32 



Superiority of the Eldest, by Corrado Gini 37 



The Proper Age for Marriage (a review) 39 



A New Walnut, by Ernest B. Babcock 40 



Prepotence in Plant Breeding, by John Belling 45 



Material for Plant Breeders (editorial note) 46 



New Publications: Heredity and Sex, by Thomas H. Morgan 47 



Race Regeneration and Law, by Havelock Ellis 47 



New Publications: Sex: Its Origin and Determination, by Thomas 



E. Reed, reviewed by Oscar Riddle 48 



Wheat X Rye Hybrids, by Fr. Jesenko. . 48 



The Journal of Heredity is published monthly by the American Genetic 

 Association (formerly called the American Breeders' Association) for the benefit 

 of its members. Fifty per cent, of the annual membership fee is specifically desig- 

 nated as payment for the Journal. Canadian members who desire to receive it 

 should send 25 cents a year, in addition to their regular membership dues of $2, 

 because of additional postage on the magazine; foreign micmbers pay 50 cents 

 extra for the same reason. Price of single copies, 25 cents. 



Entered as second-class matter August 27, 1912, at the postoflfice at Washington, 

 D. C, under the act of August 24, 1912. Contents copyrighted 1914 by the 

 American Genetic Association. Reproduction of articles or parts of articles 

 permitted provided proper credit is given to author and to the Journal of Heredity 

 (Organ of the American Genetic Association). Washington, D. C. 



Date of issue of this number, December 30, 1914. 



