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Show 174 DOMESTIC PIGEONS. C IIAP. v. greyhound with tho head of a bulldog, would b~ a. monstrous production. As fancy pigeons arc generally kept in small av1ar.rcs, and arc ab~dantly supplied with food, tl1cy must walk about much loss than tho WJld ro~kpigcon; and it may be ndmittcd as highly pr?bablo that tho roductwn in tho size of tho foot in tho twenty-two birds m tho first table. has been c:tus <l hy disusc,ss and th:tt this reduction has ::wtcd by correlatiOn on tho beaks of tho great majority of tho birds in Table I. When, o~ tho other ha~d, tho beak bas been much elongated by the continued soloctwn of successive slight increments of lcngtl1, tho foot by corrclati~n have l~ccwiso boc~mc much elongated in comparison with those of the Wild rock-p1gcon, notWithstanding their lessoned usc. As I had taken measures from tho end of the middle too to the heel of tho tar ·u in tho rock-pigeon and in tho above thirty-six birds, I have made calculations analogous with those above given, and tho result is tho samo,-namcly, that in tho short-beaked broods, with equally few exceptions as in tho former case, tho middle too conjointly with tho tarsus has decreased in length; whereas in the long-beaked breeds it has increased in length, though not quito so uniformly as in tho former case, for tho log in some varieties of tho rUllt varies much in length. As fancy pigeons arc generally confu1cd in aviaries of moderate size, and as oven when not confmod they do not search for theh own food, they must dming many generations have used their wings incomparably loss than tho wild rock-pigeon. llenco it seemed to me probable that all the parts of tho skeleton subservient to flight would he found to be l'Oducod in size. With respect to tho Fltornum, I have carefully measured its oxti·emo length in twelve bird."! of diffoJ·cnt breeds, and in two ·wild rock-pigeons from tho Shetland Islands. For tho proportional comparison I have tried with all twelve birds three standards of measurement, namely, tho length from tho base of tho beak to tho oil-gland, to tho end of tho tail, and from the extreme tip to tip of wings. Tho result has been in each case nearly tho same, the sternum being invariably found to be shorter than in the wild rock-pigeon. I will give only a single table, as calculated by tho standard from the base of tho beak to tho oil-gland; for tho result in this case is nearly tho moan between tho results obtained by tho two other standards. Length of Stemum. Name of Drccd. ILA en"g"t'h' . Too lnchcs. Short by Wiltl Rock-pigeon ... 2·55 l'hl Sc:m<leroon .. 2·80 0·60 llngadotton Carrier 2·80 0•17 Dragon .. 2·45 0•41 CtLITier 2·75 O·B5 Short-iiJ.ceu Tumbler 2·05 0·28 3 ~ In an analogous, but eonvN"se, manner, e01·tain natural groups of Uw Columbidm, from being more terrestrial in their hnbits thn.n oth r allied Actunl Name of Drced. I.&ngtb. Too lnches. Short by Barb 2·35 0•34 Nun .. 2·27 0•15 German Pouter 2•36 0•54 Jaeobin 2·33 0·22 English Frill-back .. 2•40 0·43 Swallow .. 2·45 0·17 groups, have larger feet. See Prince Bonaparte's 'Coup-cl'ooil sur l'Ordre des Pigeons.' C HAP. V. ON TilE EFFECTS OF DISUSE. 175 This table shows that in these twelve breeds the Btomum is on an average one-third of an inch (exactly ·332) shorter than in the rook-pigeon, proportionally with tho size of their bodi.cs ; so that the sternum has been reduced by between one-seventh and one-eighth of its entire length; and thjs is a considerable reduction. I have also measured in twenty-one birds, including the above dozen, tho prominence of the crest of the sternum relatively to its length, indopendently of tho size of the body. In two of the twenty-one birds the crest was prominent in tho same relative degree as in tho rock-pigeon; in seven it was more prominent; but in five out of these seven, namely, in a ti:tntail, two scandoroons, and two English carrie1·s, this greater prominence may to a certain extent be explained, as a prominent breast is admired and selected by fanciers; in tho remaining twelve birds tho prominence was loss. Renee it follows that tho crest exhibits a slight, though uncertain, tendency to become reduced in prominence in a greater dogTCo than docs tho length of tho sternum relatively to the size of body, in comparison with the rock-pigeon. I have measured tho length of tho scapula in nino different largo and small-si:r,cd breeds, and in all tho scapula is proportionally shorter (taking tho same standard as before) than in the wild rock-pigeon. Tho reduction in length on an average is very nearly one-fifth of an inch, or about one-ninth of the length of tho scapula in the rock-pigeon. The arms of tho furcula in all tho specimens which I compared, diverged loss, proportionally with the size of body, than in tho rock-pigeon; and the whole furcula was proportionally s4orter. Thus in a runt, which measured from tip to tip of wings 38} inches, tho furcula was only a very little longer (with tho arms hardly more divergent) than in a rock-pigeon which measured from tip to tip 26! inches. In a barb, which in all its measurements was a little larger than the same rock-pigeon, the furcula was a quarter of an inch shorter. In a pouter, the furcula had not been lengthened proportionally with tho increased length of the body. In a shortfaced tumbler, which measured from tip to tip ofwings 24 inches, therefore only 2~ inches less than tho rock-pigeon, tho furcula was barely two-thirds of tho length of that of the rock-pigeon. We thus clearly see that the sternum, scapulro, and furcula are all reduced in proportional length; but when we turn to the wings we find what at first appears a wholly different and unexpected result. I may here remark that I have not picked out specimens, but have used every measurement made by me. Taking the length from the base of beak to the end of the tail as the standard of comparison, I find that, out of thirty-five birds of various breeds, twenty-five have wings of greater, and ten have them of less proportional length, than in tho rock-pigeon. Bur from the frequently correlated length of the tail and wing-feathers, it is better to take as the standard |