Seite - 41 - in The Origin of Species

DOMESTIC PIGEONS 41 civilised man succeeded in thorouj^hly domesticating several species, but that he intentionally or by chance picked out extraordinarily abnormal species ; and further, that these very species have since all become extinct or unknown. So many strange contingencies are improbable in the highest degree. Some facts in regard to the colouring of pigeons well de- serve consideration. The rock-pigeon is of a slaty-blue, with white loins;' but the Indian sub-species, C. intermedia of Strickland, has this part bluish. The tail has a terminal dark bar, with the outer feathers externally edged at the base with white. The wings have two black bars. Some semi-domes- tic breeds, and some truly wild breeds, have, besides the two black bars, the wings chequered with black. These several marks do not occur together in any other species of the whole family. Now, in every one of the domestic breeds, taking thoroughly well-bred birds, all the above marks, even to the white edging of the outer tail-feathers, sometimes concur perfectly developed. Moreover, w'hen birds belonging to two or more distinct breeds are crossed, none of which are blue or have any of the above-specified marks, the mongrel off- spring are very apt suddenly to acquire these characters. To— give one instance out of several which I have observed :—I 1 crossed some white fantails, which breed very true, with some \ black barbs—and it so happens that blue varieties of barbs are so rare that I never heard of an instance in England; and the mongrels were black, brown, and mottled. I also crossed a barb with a spot, which is a white bird with a red tail and red spot on the forehead, and which notoriously breeds very true ; the mongrels were dusky and mottled. I then crossed one of the mongrel barb-fantails with a mongrel barb-spot, and they produced a bird of as beautiful a blue colour, with the white loins, double black wing-bar, and barred and white- / edged tail-feathers, as any wild rock-pigeon ! We can under-y* stand these facts, on the well-known principle of reversion to ancestral characters, if all the domestic breeds are descended from the rock-pigenn. But if we deny this, we must make one of the two following highly improbable suppositions. Either, first, that all the several imagined aboriginal stocks were coloured and marked like the rock-pigeon, although no other existing species is thus coloured and marked, so that in