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Show 80 DOMESTIC PIGEONS. [Cn.A.P. I. the domestic breeds have descended from the rock-pigeon. But if we deny this, ·we must J:?~ke one ~f the t:wo following highly imp;oba?le suppo~1~1ons. E1ther, firstly, that all the several 1ma0'1ned abong1nal stocks were coloured, and marked like the rock-pigeon, although no ot~er existing species is thus coloured and marked, so that 1n each separate breed there might be a tendency to revert to tho very sa1ne colours and markings. Or, secondly, that each breed, even the purest, has within a dozen or, at most, within a score of generations, been crossed by t~e rockpigeon: I say within a dozen or twenty generations, for we know of no fact countenancing the belief that the child ever reverts to some one ancestor, removed by a greater number of generations. In a breed which has been crossed only once with some distinct. breed, the tendency to reversion to any character denved from such cross will naturally become less and less, as in each succeeding generation there will be less of the foreign blood; but when there has been no cross with a distinct breed, and there is a tendency in both parents to revert to a character, which has been lost during some former generation, this tendency, for all that we can see to the contrary, may be trans1nitted undiminished for an indefinite number of generations. These two distinct cases are often confounded in treatises on inheritance. Lastly, the hybrids or mongrels fron1 between all the domestic breeds of pigeons are perfectly fertile. I can state this from my own observations, purposely made on the most distinct breeds. N-ow, it is difficult, perhaps impossible, to bring forward one case of the hybrid offspring of two animals clearly distinct being themselves perfectly fertile. Some authors . believe that long-continued domestication eliminates this strong tendency to sterility : from the history of the dog I think there is some probability in this hypothesis if applied to species closely related together, though it is unsupported by a single experin1ent. But to extend the hypothesis so far as to suppose that species, aboriginally as distinct as carriers, tumblers, pouters, and fantails now aTe, should yield offspTing perfectly fertile, inter se, seems to me rash in the extreme. CHAP. I.] DOMESTIC PIGEONS. 31 Frorn these several reasons, namely, the improbability of man having formerly ~ot seven or eight supposed species of pigeons to breed freely under domestication ; these supposed species being quite unknown in a wild state, and their becoming nowhere feral; these species having very abnormal characters in certain respects, as compared with all other Columbidre, though so like in most other respects to the rock-pigeon; the blue colour and various 1narks occasionally appearing in all the breeds, both when kept pure and when crossed ; the mongrel offspring being perfectly fertile ;-from these several reasons, taken together, I can feel no doubt that all our domestic breeds have descended from the Columba livia with its geographical sub-species. In favour of this view, I may add, firstly, that C. livia, or the rock-pigeon, has been found capable of dontestication in Europe and in India; and that it agrees in habits and in a great number of points of structure with all the domestic breeds. Secondly, although an English carrier or short-faced tumbler differs immensely in certain characters from the rock-pigeon, yet by co1nparing the several sub-breeds of these breeds, more especially those brought from distant countries, we can make an almost perfect series between the extremes of structure. Thirdly, those characters which are mainly distinctive of each breed, for instance the wattle and length of beak of the carrier, the shortness of that of the turnbler, and the number of tailfeathers in the fantail, are in each breed eminently variable; and the explanation of this fact will be obvious when we come to treat of selection. Fourthly, pigeons have been watched, and tended with the utmost care, and loved by many people. They have been domesticated for thousands of years in several quarters of the world ; the earliest known record of pigeons is in the fifth .LEgyptian dynasty, about 3000 n. c., as was pointed out to me by Professor Lepsius ; but Mr. Birch informs me that pigeons are given in a bill of fare in the previous dynasty. In the time of the Romans, as we hear from Pliny, immense prices were given for pigeons; "nay, they are come to this pass, that they can reckon up their pedigree and |