POLYGAMOUS FACTORS 79 



neous entries again enclosed within brackets, are as 

 follows : 



Bays 



With bay mares 18 bay Shires get 366 

 With black mares the same sires 



get 51 



With bay mares 10 bay German 



sires get .... 141 

 With black mares the same sires 



get 105 



Thus we have a series of three colours, bay, black, 

 and chestnut, in which bay is dominant to black and 

 chestnut, and black to chestnut, and each colour is the 

 result of a single factor which mates separately and 

 indifferently with either of the factors for the other 

 two colours. 



The foregoing proof of this hypothesis may be con- 

 firmed still farther. If it be sound, then there should 



Bv 



be pure bays, constitutionally represented by -„ , bays 



Bv 



carrying the black factor, p^, and bays carrying the 



chestnut factor, „^, pure blacks, ^j,, blacks carrying 



Bl Ch 



chestnut „, , and chestnuts, „, . Then, in a mixed popu- 

 lation of bays, blacks, and chestnuts, there shouldT be 

 sires and dams of each of these six constitutions, and the 

 different varieties of bay and black sires should leave 

 different assemblages of progeny as indicated in the 

 following table ; 



