In the Indian Frizzled fowl, which cannot fly, the reduction is carried to
the greatest extent, namely, to thirty-three per cent of their proper
proportional weight. In the next four birds, including the Silk hen, which
is incapable of flight, we see that the wings, relatively to the legs, are
slightly increased in weight; but it should be observed that, if in these
birds the legs had become from any cause reduced in weight, this would give
the false appearance of the wings having increased in relative weight. Now
a reduction of this nature has certainly occurred with the Burmese Jumper,
in which the legs are abnormally short, and in the two Hamburghs and Silk
fowl, the legs, though not short, are formed of remarkably thin and light
bones. I make these statements, not judging by mere eyesight, but after
having calculated the weights of the leg-bones relatively to those of G.
bankiva, according to the only two standards of comparison which I could
use, namely, the relative lengths of the head and sternum; for I do not
know the weight of the body in G. bankiva, which would have been a better
standard. According to these standards, the leg-bones in these four fowls
are in a marked manner far lighter than in any other breed. It may
therefore be concluded that in all cases in which the legs have not been
through some unknown cause much reduced in weight, the wing-bones have
become reduced in weight relatively to the leg-bones, in comparison with
those of G. bankiva. And this reduction of weight may, I apprehend, safely
be attributed to disuse.
To make Table 7.I. quite satisfactory, it ought to have been shown that in
the eight first birds the leg-bones have not actually increased in weight
out of due proportion with the rest of the body; this I cannot show, from
not knowing, as already remarked, the weight of the wild Bankiva. (7/74.
Mr. Blyth (in 'Annals and Mag. of Nat. Hist.' 2nd series volume 1 1848 page
456) gives 3 1/4 pounds as the weight of a full-grown male G. bankiva; but
from what I have seen of the skins and skeletons of various breeds, I
cannot believe that my two specimens of G. bankiva could have weighed so
much.) I am indeed inclined to suspect that the leg-bones in the Dorking,
No. 2 in the table, are proportionally too heavy; but this bird was a very
large one, weighing 7 pounds 2 ounces, though very thin. Its leg-bones were
more than ten times as heavy as those of the Burmese Jumper! I tried to
ascertain the length both of the leg-bones and wing-bones relatively to
other parts of the body and skeleton: but the whole organisation in these
birds, which have been so long domesticated, has become so variable, that
no certain conclusions could be reached. For instance, the legs of the
above Dorking cock were nearly three-quarters of an inch too short
relatively to the length of the sternum, and more than three-quarters of an
inch too long relatively to the length of the skull, in comparison with
these same parts in G. bankiva.
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