INDEX 



219 



Single comb, 29 



Size, inheritance of, 164 



Species, nature of, 181 



origin of, 10 

 Spermatozoa, 3 

 Sports, 179 



Staples-Browne, R., 61 

 Sterility, 182 



in sweet-peas, 115, 131 

 Stocks, double, 153 



hoariness in, 50 

 Sweet-pea, colour in, 41, 74 



history of, tj 



sex in, 114 



size in, 57 



sterility in, 115, 131 



Telegony, 197 

 Thrum-eye in primulas, 51 

 Toe, extra toe in poultry, 70 



Tortoiseshell cats, 109 

 Tschermak, E. , 26 



Unit-characters, 28 



Variation, 13 



Vigour, increased from cross, 166 



Walnut comb, 29 

 Weismann, A., 12 

 Wheat, beard in, 69 



experiments with, 188 

 White, in poultry, 67 

 Wilson. J.. 198 



X chromosomes, 103 



F chromosomes, 103 

 Yellow mice, 150 



Zygotes, nature of, 5 



THE END 



Printed in Great Britain l>y R. & R. Clark, Limited, Edinburgh. 



