410 Ml-. R. 1. Pocock on the Colours of 



nearest to the hypothetical wild type that was so colourec?. 

 Whether he was tall in stature or a pony, heavily or lightly 

 built, long- or short-headed, must be left, at all events for 

 the present, undecided. It is, in my opinion, almost certain 

 that crossing of different breeds, whether intentionally selec- 

 tive or not, together with changed conditions of life, have 

 so altered domestic horses^ that no existing grey resembles, 

 except in colour, and perhaps not exactly in that, the hypo- 

 thetical wild prototype. Welsh and Airedale terriers have 

 reverted nearly to the coloration of jackals without in them- 

 selves resembling jackals in structure. 



According to Prof. Ridgeway * there is justification for 

 the conclusion " that grey horses are not an original stock 

 . . . but are the result of crossing Libyan and Asiatic blood." 

 I presume from this that Prof. Ridgeway holds that dapple- 

 greys with tlie mane, tails, and lower legs mostly black are 

 hybrids or mongrels or " sports " in the sense that chestnuts 

 are sports, a view which may be perfectly correct f. Never- 

 theless I do not think it follows that dapple-grey was not a 

 primitive colour because it comes out in the progeny when 

 the parents belong to distinct stocks, whether they be breeds, 

 subspecies, or species ; for, as Darwin pointed out, the 

 offspring of distinct breeds may revert to the coloration of 

 remote ancestors. Hence, if "dapple-grey" results from 

 crossing bay Libyan with dun Asiatic horses, the fact may 

 be cited as an item of evidence in favour of the possibly 

 primitive nature of that pattern. This, at all events, is a 

 suggested explanation of what is otherwise, if true, a remark- 

 able phenomenon in inheritance. 



But the dapple-grey pattern is interesting from another 

 point of view. As already said, a horse so coloured may be 

 described with perfect accuracy either as a dark horse with 

 white spots or as a white horse with dark reticulations, just 

 as zebras may be described as black animals with white or 

 fawn stripes or as white or fawn animals with black stripes. 

 Up to the present time it has been almost universally ad- 

 mitted that in the Equidse the black markings constitute the 

 stripes and the white or fawn the ground-colour to which the 

 stripes have been superadded, as in the case of the .^Eluroid 

 Carnivora. Sir Harry Johnston J, however, thinks this view 



* ' Origin and Influence of the Thoroughbred Horse,' p. 261 (1905). 



t Compare, however, Hamilton Smith, who said " albinism would 

 produce white or flea-bitten or sorrel horses, but does not afford the 

 round dapples and blade legs " (" Horses " in the ' Naturalist's Library,' 

 Mammalia, vol. xii. p. 211, 1841). 



X ' The Wobum Library : British Mammals,' pp. 276 277 (1903). 



