[24] Something of the same kind has occurred on the island of Lipari, where, according to Spallanzani (‘Voyage dans les deux Siciles,’ quoted by Godron, ‘De l’Espèce,’ p. 364), a countryman turned out some rabbits which multiplied prodigiously, but, says Spallanzani, “les lapins de l’ile de Lipari sont plus petits que ceux qu’on élève en domesticité.”
[25] Waterhouse, ‘Nat. Hist. Mammalia,’ vol. ii. p. 36.
[26] These rabbits have run wild for a considerable time in Sandon Park, and in other places in Staffordshire and Shropshire. They originated, as I have been informed by the gamekeeper, from variously-coloured domestic rabbits which had been turned out. They vary in colour; but many are symmetrically coloured, being white with a streak along the spine, and with the ears and certain marks about the head of a blackish-grey tint. They have rather longer bodies than common rabbits.
[27] See Prof. Owen’s remarks on this subject in his paper on the ‘Zoological Significance of the Brain, etc., of Man, etc.,’ read before Brit. Association 1862: with respect to Birds, see ‘Proc. Zoolog. Soc.,’ Jan. 11, 1848, p. 8.
[28] This standard is apparently considerably too low, for Dr. Crisp (‘Proc. Zoolog. Soc.,’ 1861, p. 86) gives 210 grains as the actual weight of the brain of a hare which weighed 7 pounds, and 125 grains as the weight of the brain of a rabbit which weighed 3 pounds 5 ounces, that is, the same weight as the rabbit No. 1 in my list. Now the contents of the skull of rabbit No. 1 in shot is in my table 972 grains; and according to Dr. Crisp’s ratio of 125 to 210, the skull of the hare ought to have contained 1632 grains of shot, instead of only (in the largest hare in my table) 1455 grains.
CHAPTER V.
DOMESTIC PIGEONS.
ENUMERATION AND DESCRIPTION OF THE SEVERAL BREEDS—INDIVIDUAL VARIABILITY—VARIATIONS OF A REMARKABLE NATURE—OSTEOLOGICAL CHARACTERS: SKULL, LOWER JAW, NUMBER OF vertebræ—CORRELATION OF GROWTH: TONGUE WITH BEAK; EYELIDS AND NOSTRILS WITH WATTLED SKIN—NUMBER OF WING-FEATHERS, AND LENGTH OF WING—COLOUR AND DOWN—WEBBED AND FEATHERED FEET—ON THE EFFECTS OF DISUSE—LENGTH OF FEET IN CORRELATION WITH LENGTH OF BEAK—LENGTH OF STERNUM, SCAPULA, AND FURCULUM—LENGTH OF WINGS—SUMMARY ON THE POINTS OF DIFFERENCE IN THE SEVERAL BREEDS.
I have been led to study domestic pigeons with particular care, because the evidence that all the domestic races are descended from one known source is far clearer than with any other anciently domesticated animal. Secondly, because many treatises in several languages, some of them old, have been written on the pigeon, so that we are enabled to trace the history of several breeds. And lastly, because, from causes which we can partly understand, the amount of variation has been extraordinarily great. The details will often be tediously minute; but no one who really wants to understand the progress of change in domestic animals, and especially no one who has kept pigeons and has marked the great difference between the breeds and the trueness with which most of them propagate their kind, will doubt that this minuteness is worth while. Notwithstanding the clear evidence that all the breeds are the descendants of a single species, I could not persuade myself until some years had passed that the whole amount of difference between them, had arisen since man first domesticated the wild rock-pigeon.
I have kept alive all the most distinct breeds, which I could procure in England or from the Continent; and have prepared skeletons of all. I have received skins from Persia, and a large number from India and other quarters of the world.[[1]] Since my admission into two of the London pigeon-clubs, I have received the kindest assistance from many of the most eminent amateurs.[[2]]
The races of the Pigeon which can be distinguished, and which breed true, are very numerous. MM. Boitard and Corbié[[3]] describe in detail 122 kinds; and I could add several European kinds not known to them. In India, judging from the skins sent me, there are many breeds unknown here; and Sir W. Elliot informs me that a collection imported by an Indian merchant into Madras from Cairo and Constantinople included several kinds unknown in India. I have no doubt that there exist considerably above 150 kinds which breed true and have been separately named. But of these the far greater number differ from each other only in unimportant characters. Such differences will be here entirely passed over, and I shall confine myself to the more important points of structure. That many important differences exist we shall presently see. I have looked through the magnificent collection of the Columbidæ in the British Museum, and, with the exception of a few forms (such as the Didunculus, Calænas, Goura, etc.), I do not hesitate to affirm that some domestic races of the rock-pigeon differ fully as much from each other in external characters as do the most distinct natural genera. We may look in vain through the 288 known species[[4]] for a beak so small and conical as that of the short-faced tumbler; for one so broad and short as that of the barb; for one so long, straight, and narrow, with its enormous wattles, as that of the English carrier; for an expanded upraised tail like that of the fantail; or for an œsophagus like that of the pouter. I do not for a moment pretend that the domestic races differ from each other in their whole organisation as much as the more distinct natural genera. I refer only to external characters, on which, however, it must be confessed that most genera of birds have been founded. When, in a future chapter, we discuss the principle of selection as followed by man, we shall clearly see why the differences between the domestic races are almost always confined to external, or at least to externally visible, characters.