114 . THE GENESIS OF SPECIES. [Chap. 



reversion ; and if this be so, wo arc forced to admit tha 

 somewhat comj)lex, thougli a{)parently useless structures 

 may be suddenly developed without the aid of selection." 

 Again, " Climate directly affects the thickness of the skin 

 and hair" of cattle." In the English climate an individual 

 Porto Santo rabbit' recovered the proper color of its fur in 

 rather less than four years. The ell'ect of the climate of 

 India on the turkey is cinisiderable. Mr. IJlyth '" describes 

 it as being much degenerated in size, " utterly incapable 

 of rising on the wing," of a black color, and " with long 

 pendulous appendages over the beak enormously de- 

 veloped." Mr. Darwin again tells us that there has sud- 

 denly appeared in a bed of common broccoli a peculiar va- 

 riety, faithfully transmitting its newly-ac(|uircd and remark- 

 able characters ; ** also that there have been a rapid trans- 

 formation and transplantation of American varieties of 

 maize with a European variety ; '^ that certainly " the An- 

 con and Manchamp breeds of sheep," and that (all but cer- 

 tainly) Niata cattle, turnspit and pug dogs, jumper and 

 frizzled fowls, sh(jrt-faced tuml)ler j)igeons, hook-billed 

 ducks, etc., and a multitude of vegetable varieties, have 

 suddenly ai)peared in nearly the same state as we now see 

 them." Lastly, Mr. Darwin tells us that there has been 

 an occasional development (in five distinct cases) in Eng- 

 land of the "japanned" or "black-shouldered peacock," 

 (Pavo Qiigripennis)^ a distinct species, according to Dr. 

 Sclater,'* yet arising in Sir J. Trevelyan's flock composed 

 entirely of the common kind, and increasing, " to the extinc- 

 tion of the 2yrevioi(slt/-existin(f breeds ^^ Mr. Darwin's only 

 explanation of the phenomena (on the supposition of the 



* "Animals anil Plants unilcr Domestication," vol. i., p. 7 1. 



» Ibid., p. lU. »" t^iutcd, iliid., p. 274. " ll»iil., p. :i21. 



'2 Ibid., p. 322. 13 Ibid., vol. ii., p. 411. 



" Proc. Zool. Soo. of Loudon, April 21, 1800. 



'* " Animals and Plants under Domestication," vol. i., p. 291. 



