Origin of Species Variorum

Comparison with 1869

their six-days old puppies, I found that the puppies had not acquired nearly their full amount of proportional difference. So, again, I was told that the foals of cart and race-horses— breeds which have been almost wholly formed by selection under domestication— differed as much as the full-grown animals; ... but having had careful measurements made of the dams and of .. three-days old colts of race-horses and heavy cart-horses, I find that this is by no means the case.

As we have conclusive evidence that the .. breeds of the Pigeon are descended from a single wild species, I compared the young within twelve hours after being hatched; I carefully measured in the wild parent-species, in pouters, fantails, runts, barbs, dragons, carriers, and tumblers, the proportions (but will not here give the details) of the beak, width of mouth, length of nostril and of eyelid, size of feet and length of leg. .. .. .. .. .. .. .. .. .. .. .. .. .. Now some of these birds, when mature, differ in so extraordinary a degree in the length and form of beak, and in other characters, that they would, certainly be ranked as distinct genera if found in a state of nature. But when the nestling birds of these several breeds were placed in a row, though most of them could just be distinguished, yet the proportional differences in the above specified .. points were incomparably less than in the full-grown birds. Some characteristic points of difference— for instance, that of the width of mouth— could hardly be detected in the young. But there was one remarkable exception to this rule, for the young of the short-faced tumbler differed in all its proportions from the young of the wild rock-pigeon and of the other breeds, ... almost exactly as much as in the adult state.

As the evidence appears to me conclusive, that the several domestic breeds of Pigeon have descended from one wild species, I compared young pigeons of various breeds, within twelve hours after being hatched; I carefully measured the proportions (but will not here give details) of the beak, width of mouth, length of nostril and of eyelid, size of feet and length of leg, in the wild stock, in pouters, fantails, runts, barbs, dragons, carriers, and tumblers. Now some of these birds, when mature, differ so extraordinarily in length and form of beak, that they would certainly have been ranked as distinct genera, had they been natural productions. But when the nestling birds of these several breeds were placed in a row, though most of them could be distinguished from each other, yet their proportional differences in the above specified several points were incomparably less than in the full-grown birds. Some characteristic points of difference— for instance, that of the width of mouth— could hardly be detected in the young. But there was one remarkable exception to this rule, for the young of the short-faced tumbler differed from the young of the wild rock-pigeon and of the other breeds, in all its proportions, almost exactly as much as in the adult state.