Wilson — The Inheritance of Coat Colour in Horses. 343 



Perhaps the most interesting colour of all is the one set aside earlier in 

 the paper for separate consideration, viz., roan. There are only a few 

 entries of roans in the Thoroughbred and Clydesdale stud-books ; but inquiry 

 brought out the fact that there are more horses of this colour in both breeds 

 than the stud-books would make out. It is an unpopular colour among 

 Thoroughbreds and Clydesdales, and when a breeder sees, say, a bay foal 

 " with a grey hair througli " its coat, it is easy for him to believe the foal to 

 be a bay and not a roan. 



On the other hand, roans are not altogether unpopular among Shires ; 

 and a good many are to be found in the stud-book, especially in the earlier 

 volumes. We were therefore driven back upon the data collected from 

 the first ten volumes of the Shire stud-book for examples of the be- 

 haviour of roan. It has been stated already that, in collecting these data, 

 several theories suggested themselves ; and the one that roans are hybrids 

 between grey and some one of the other colours seemed a priori the most 

 likely. But greys never, or at any rate very seldom, and then doubtfully, 

 produced roans with those other colours; and the crossing of roan with roan 

 was too infrequent to give any guidance. Eventually it became evident 

 that roan was separate from grey, but that its behaviour towards the other 

 colours was similar, while at the same time it had a peculiarity of its own. 



Grey, as we have already found, is dominant in the other colours — brown, 

 bay, black, and chestnut. This means that, in a population of the above 

 colours, there can be no grey foal without, at least, one grey parent, and 

 that, if the pedigree of a grey foal be followed backwards as far as it is 

 known, a grey ancestor will be found in every generation. The following 

 examples might be given : — 



A Thoroughbred Example.' A Clydesdale Example. 



The Drone, grey (foaled 1823), X Kiss (foaled 1827). Blyth, grey (foaled 1836 or 1837). 



Irish Birdcatcher, X Whim, grey. Clydesdale Jock, grey, 



chestnut. I I 



Chanticleer, grey, X Birthday, bay or brown. Donald Blue, grey, X Mare, brown. 



Newminster, bay, X Souvenir, grey. The Diike, X Mare, grey. 



I chestnut. I 



Strathconan, grey, X Sweet Violet, bay. Sultan, X Mare, grey. 



I Hack. I 



Linnaeus, grey, X Dulcie Agnes, brown. Glengarry, X Belle of Burnaide, colour not stated. 



I bay. I 



Linny, grey, X Lady Blue, brown. Mains of ) X Eose of Meikle Folia, grey. 



I Airies, j brown I 



Sidestrand, grey (foaled 1903). EozeUe, X Blue Bell of Meikle FoUa, grey. 



bay. j 



Kozabelle, grey (foaled 1907). 



' Sires are placed to the left, dams to the right. 



