188 Scientific Proceedings, Royal Dublin Society. 



horses. A uumber of dun horses have been examined and the parentage of 

 some of them looked into, but only three are cited, none of whose parents is 

 dun. Darwin then sums up : — " From reasons which will appear in the 

 chapter on Reversion I have endeavoured, but with poor success, to discover 

 whether duns, which are so ranch oftener striped than other coloured horses, 

 are ever produced from the crossing of two horses, neither of which are duns. 

 Most persons to whom I have appealed believe that oue parent must be a dun ; 

 and it is generally asserted that, when this is the case, the dun-colour and the 

 stripes are strongly inherited. One case has fallen under my own observation 

 of a foal from a black mare by a bay horse, which when fully grown, was a 

 dark fallow-dun and had a narrow but plain spinal stripe. Hofacker gives 

 two instances of mouse-duns (Mausrapp) being produced from two parents of 

 different colours and neither duns."^ 



On these grounds Darwin adds the dun colour to the stripes of the 

 ancestral horse. But he says that the case for the descent of the horse from 

 a dun and striped ancestor is less clear than that of tlie pigeon from a blue 

 and barred ancestor : — " The appearance of the stripes on the various breeds 

 of the horse when of a dun-colour does not afford nearly such good evidence 

 of their descent from a single primitive stock as in the case of the pigeon. . . . 

 Nevertheless tlie similarity in the most distinct breeds in their general range 

 of colour, in their dappling, and in the occasional appearance, especially in 

 duns, of leg-stripes, and of double or triple shoulder-stripes, taken together, 

 indicate the probability of the descent of all the existing races from a single, 

 dun-coloured, more or less striped, primitive stock, to which our horses still 

 occasionally revert."' 



Curiously enough, in the argument leading to the statement just quoted, 

 there is no mention of Lord Morton's experiment, from which it might be 

 inferred that the second and third foals^ from the chestnut mare carried 

 weight in Darwin's mind no longer. But this is scarcely possible ; for they 

 are cited in a subsequent chapter'' in language which suggests that Darwin 

 took them to be more dun tlian Lord Morton did. Lord Morton spoke of 

 the filly and the colt generally as both resembling the quagga in their colour, 

 and particularly, of tlie filly's dun tint, which consisted in the colour of the 

 neck approaching to dun and in the same jjale tint in a less degree appearing on 

 the rump. But Darwin wrote : — " These colts were partially dun-coloured, 

 and were striped on the legs more plainly than the real hybrid, or even than 



' "Animals and Plants under Domestication " (186S), i, p. 59. - Hid., p.' 61. 



^ There was also a fourth foal born after Lord Morton's communication very like the second and 

 third. Their portraits are in the Eoyal College of Surgeons Museum in London. 

 ^ " Animals and Plants under Domestication," i, p. 403. 



