POLYGAMOUS FACTORS 89 



The data concerning dun are so few that it is impos- 

 sible to give that colour similarly full treatment. One 

 result, however, is sufficient to show that it is parallel 

 with the other colours. When hybrid duns were mated 

 with colours lower in the series, equal numbers of duns 

 on the one hand and of all the other colours together on 

 the other were produced. The numbers are duns 55, 

 bays 43, blacks 9, and chestnuts 3. It might also be 

 mentioned that Brilliant, a dun Thoroughbred 'foaled in 

 1750, containing chestnut recessive, got 5 duns, 1 bay, 

 1 black, and 1 chestnut with bay mares, and 1 dun 

 and 1 chestnut with chestnut mares. 



Not the least interesting point in connexion with this 

 series of colours is that it does not end with the horse 

 but continues down to the donkey, whose colours are 

 recessive to every horse colour. This is evident from the 

 fact that mules are always one or other of the colours 

 belonging to the horse ; and not only so, but chestnut 

 mules are chestnut right down to the heels just as 

 chestnut horses are, while bay mules {i.e. bays and 

 browns) have not only the black " points " but also the 

 light or tan muzzle as they are found in bay horses. 

 The only two dun mules the writer has ever seen had 

 black " points " just as they are usually found in dun 

 horses ; and grey mules become grey gradually just like 

 grey horses. 



Indeed it is possible that the series continues into the 

 colours of all the Equida^, for, if their striping be 

 neglected — and striping is probably the result of separate 

 factors — the Zebra hybrids bred by Professor Cossar 

 Ewart were scarcely, if at all, distinguishable from 

 horses, in the matter of colour. 



