ILLUSTRATIONS 



OVARIAN TRANSPLANTATION (Plate IV) 



(p. Ill) Frontispiece 



From photographs in the possession of Professor 

 W. E. Castle. 



FEMINIZED GUINEA-PIGS (Plate I) ... 52 



By courtesy of Professor E. Steinach. 



MENDELIAN INHERITANCE (Plate II) ... 86 



From photographs in the possession of Professor 

 W. E. Castle. 



UNIT CHARACTERS (Plate III) 92 



From photographs in the possession of Professor 

 W. E. Castle, 



