POLYGAMOUS FACTORS 83 



whose parents' colours could be determined had one 

 dun parent. It was also found to be similar with most 

 recent duns. Thus dun seemed dominant to all other 

 colours, not excluding grey : but, when the records of 

 their progeny were examined, it was found that duns, 

 though they leave all colours, leave no greys unless 

 the other parent be a grey. Thus dun is recessive to 

 grey. 



The position thus assigned to dun was confirmed by 

 the progeny of two dun sires, Oscar and Norseman, 

 stationed on Clare Island off the coast of Mayo, the 

 former from 1901 to 1903 and the latter from 1904 to 

 1906. The mares on the island were of all colours ; 

 no other sires were there at the same time ; and all the 

 progeny of both sires were dun. In 1908, another dun 

 sire, obviously a hybrid, was placed on the island, and, 

 while more than half his progeny were duns, the 

 remainder, with a grey exception which was out of a 

 grey mare, were of the ordinary colours. 



There remains still another colour, cream, but, as 

 the evidence regarding it is very scanty, all that can be 

 said is that it may be a variety shade of dun. 



Thus we have a series of five colours, grey, dun, bay, 

 black, and chestnut, in which those coming first are 

 dominant to all coming later and those coming later 

 recessive to all before them. And it has been shown 

 that bay, black, and chestnut are each the result of 

 single polygamous factors. But the question still 

 remains : Are grey and dun also the result of single 

 polygamous factors ? It is scarcely conceivable they 

 could be otherwise, for, then, they would carry factors 

 which could find no other factors to mate with in bay, 

 black, and chestnut. 



