Chap. VIII. PEACOCK. 291 



common kind, and in Mr. Thornton's stock of common and pied 

 peacocks. It is remarkable that in these two latter instances 

 the black-shouldered kind increased, " to the extinction of the 

 previously existing breed." I have also received through Mr. 

 Sclater a statement from Mr. Hudson Gurney that he reared 

 many years ago a. pair of black-shouldered peacocks from the 

 common kind ; and another ornithologist, Prof. A. Newton, states 

 that, five or six years ago, a female bird, in all respects similar 

 to the female of the black-shouldered kind, was produced from a 

 stock of common peacocks in his possession, which during more 

 than twenty years had not been crossed with birds of any other 

 strain. Here we have five distinct cases of japanned birds sud- 

 denly appearing in flocks of the common kind kept in England. 

 Better evidence of the first appearance of a new variety could 

 hardly be desired. If we reject this evidence, and believe that 

 the japanned peacock is a distinct species, we must suppose in 

 all these cases that the common breed had at some former period 

 been crossed with the supposed P. nigripennis, but had lost 

 every trace of the cross, yet that the birds occasionally produced 

 offspring which suddenly and completely reacquired through 

 reversion the characters of P. nigripennis. I have heard of no 

 other such case in the animal or vegetable kingdom. To per- 

 ceive the full improbability of such an occurrence, we may sup- 

 pose that a breed of dogs had been crossed at some former 

 period with a wolf, but had lost every trace of the wolf-like 

 character, yet that the breed gave birth in five instances in the 

 same country, within no great length of time, to a wolf perfect 

 in every character ; and we must further suppose that in two of 

 the cases the newly produced wolves afterwards spontaneously 

 increased to such an extent as to lead to the extinction of the 

 parent-breed of dogs. So remarkable a form as the P. nigri- 

 pennis, when first imported, would have realized a large price ; 

 it is therefore improbable that it should have been silently in- 

 troduced and its history subsequently lost. On the whole the 

 evidence seems to me, as it did to Sir R. Heron, to preponderate 

 strongly m favour of the black-shouldered breed being a varia- 

 tion, induced either by the climate of England, or by some 

 unknown cause, such as reversion to a primordial and extinct 

 condition of the species. On the view that the black-shouldered 



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