Proceedings of the American Academy of Arts and Sciences. 

 Vol. XXXIX. No. 8. — November, 1903. 



CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE 

 MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD COLLEGE. 

 E. L. MARK, DIRECTOR. — No. 146. 



THE LAWS OF HEREDITY OF G ALT ON AND MENDEL, 



AND SOME LAWS GOVERNING RACE 



IMPROVEMENT BY SELECTION. 



By ^y. E. Castle. 



