Chap. VII. THEIE PARENTAGE. 233 



higher than their former standard; as has actually occurred 

 quite recently with Polish fowls. If, however, a breed were 

 utterly neglected, it would become extinct, as has recently hap- 

 pened with one of the Polish sub-breeds. Whenever in the 

 course of past centuries a bird appeared with some slight ab- 

 normal structure, such as with a lark-like crest on its head, 

 it would probably often have been preserved from that love of 

 novelty which leads some persons in England to keep rump- 

 less fowls, and others in India to keep frizzled fowls. And 

 after a time any such abnormal appearance would be carefully 

 preserved, from being esteemed a sign of the purity and excel- 

 lence of the breed ; for on this principle the Bomans eighteen 

 centuries ago valued the fifth toe and the white ear-lobe in 

 their fowls. 



Thus from the occasional appearance of abnormal characters, 

 though at first only slight in degree ; from the effects of the use 

 and the disuse of parts; possibly from the direct effects of 

 changed climate and food ; from correlation of growth ; from 

 occasional reversions to old and long-lost characters ; from the 

 crossing of breeds, when more than one had once been formed ; 

 but, above all, from unconscious selection carried on during 

 many generations, there is no insuperable difficulty, to the best 

 of my judgment, in believing that all the breeds have descended 

 from some one parent-source. Can any single species be named 

 from which we may reasonably suppose that all have descended ? 

 The Gallus bankiva apparently fulfils every requirement. I have 

 already given as fair an account as I could of the arguments in 

 favour of the multiple origin of the several breeds ; and now I will 

 give those in favour of their common descent from G. bankiva. 



But it will be convenient first briefly to describe all the known species 

 o brallus. The Q. Sonneratii does not range into the northern parts of 

 India; according to Colonel Sykes, 12 it presents at different heights on 



e Unauts, two strongly marked varieties, perhaps deserving to be called 



pecies It was at one time thought to be the primitive stock of all our 



aomestic breeds, and this shows that it closely approaches the common fowl 



general structure ; but its hackles partially consist of highly peculiar, 

 norny lammse, transversely banded with three colours; and I have met 

 witn no authentic account of any such character having been observed 



12 « Proa Zoolog. Soc' 1832, p. 151. 



