e Journal of 



HEREDITY 



yj montlm pmlicaim dewkd tojkdjjreedim 

 Animal JjreedimcutdEuamics 





DECEMBER, 1919 

 Vol. X, No. 9 



THIS ISSUE 



DEVOTED ENTIRELY 



TO TWINS 



ORGAN OF THE 



AMERICAN GENETIC ASSOCIATION 



WASHINGTON • D G. 



jrintedfor QivcuLaliovt among "MamUrs only 



Aecpotanop for mailing at the soeciaj r»t« of postage provided tor in Mcdoa tl03. Act ol October \ 1917 



•«tfacinzed December 20, Vi\9. 



