On the Inheritance of Coat Colour in Horses. 389 



which is recessive.* For example, the bay and brown sires St. Simon, St. Serf, 

 Galopin, Ladas, Merry Hampton, and Cabin Boy, mated with numerous chest- 

 nut mares, gave 370 foals, all of which were bays or browns. • The following 

 table gives the individual numbers : — 



Table I (DD x RR). 



Pure Dominant Bay and Brown Sires, Mated with Recessive Chestnut 



Mares. 



Sires. 



Bay and brown 

 foals. 



Chestnut 

 foals. 



Total. 



St. Simon 



96 







96 



St. Serf 



83 







83 



Galopin 



62 







62 





56 







56 



Merry Hampton 



44 







44 



Cabin Boy 



29 







29 



Totals 



370 







370 



The above numbers not only show the Mendelian dominance of bay and 

 brown over chestnut, but they also prove that the individual sires concerned 

 are homozygous bays and browns giving off no chestnut gametes. 



It may be noted that all these sires had bay or brown parents and grand- 

 parents except St. Serf, which had a chestnut grandparent. 



Further records show that other bay and brown sires are heterozygous, 

 giving off chestnut gametes on the average in equal numbers, in accordance 

 with the Mendelian expectation. 



For instance, the bay and brown sires Royal Hampton, Donovan, St. Angelo, 

 Isinglass, Orvieto, Ayrshire, Florizel II, Pioneer, Isonomy, Melton, Wisdom, 

 and Rose Window, mated with numerous chestnut mares, gave 702 foals, of 

 which 355 were bays and browns and 347 were chestnuts. These numbers 

 are close to the Mendelian expectation of equality. 



The following table gives the individual numbers : — 



* In the recent volumes, about 95 per cent, of the colours registered are bay, brown, or 

 chestnut, the small remainder consisting of black, grey, roan, and other colours. 



