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1859
1860
1861
1866
1869
1872

Compare with:
1859
1861
1866
1869
1872

And the cases just given, more especially that of pigeons, seem to show that the characteristic differences which give value to each breed, and which have been 1859 1860 1861
Fanciers select their horses, dogs, and pigeons, for breeding, when they are nearly grown up: they are indifferent whether the desired qualities and structures have been 1866
And the cases just given, more especially that of pigeons, show that the characteristic differences which give value to the breeds and which have been 1869
Fanciers select their dogs, horses, pigeons, &c., for breeding, when nearly grown up: they are indifferent whether the desired qualities are 1872

accumulated by mans selection, have not generally first appeared at an early period of life, and have been inherited by the offspring at a corresponding not early period. 1860
accumulated by man's selection, have not generally first appeared at an early period of life, and have been inherited by the offspring at a corresponding not early period. 1859 1861
acquired earlier or later in life, if the full-grown animal possesses them. 1866 1872
accumulated by mans selection, have not generally appeared at a very early period of life, and have been inherited at a corresponding not early period. 1869

of the short-faced tumbler, which when twelve hours old had acquired its proper proportions, proves that this is not the universal rule; for here 1859 1860 1861
just given, more especially that of pigeons, seem to show that 1866
of the short-faced tumbler, which when twelve hours old possessed its proper characters, proves that this is not the universal rule; for here 1869
just given, more especially that of the pigeons, show that 1872

must either have appeared at an earlier period than usual, or, if not so, the differences must 1859 1860 1861 1869
which give value to each breed, and which 1866
which 1872

inherited, not at the corresponding, but 1859 1860 1861
accumulated by man's selection, have not generally first appeared 1866
inherited, not at a corresponding, but 1869
accumulated by man's selection, and which give value to his breeds, do not generally appear 1872

earlier age. 1859 1860 1861 1869
early period of life, and have been inherited by the offspring at a corresponding not early period. 1866
early period of life, and are inherited at a corresponding not early period. 1872

1 blocks not present in 1859 1860 1861 1869; present in 1866 1872
But the case of the short-faced tumbler, which when twelve hours old had acquired its proper proportions, proves that this is not the universal rule; for here the characteristic differences must either have appeared at an earlier period than usual, or, if not so, the differences must have been inherited, not at the corresponding, but at an earlier age.

facts and the above two principles— which latter, though not proved true, can be shown to be in some degree probable— 1859 1860 1861
facts and the above two principles 1866
two principles 1869 1872

on my theory 1859 1860 1861 1866
OMIT 1869 1872

one parent-species, and of which the several new species have become 1859 1860 1861 1866
ancient form and 1869 1872

in accordance with their diverse 1859 1860 1861 1866
for different 1869 1872

at a rather late 1859 1860 1861 1866
in the several species at a not early 1869 1872

of the new species of our supposed genus will manifestly tend to 1859 1860 1861 1866
will be left but little modified and will 1869
will have been but little modified, and they will still 1872

whole families or even 1859 1860 1861 1866
widely distinct structures and to whole 1869 1872

in the parent-species, may have become, by 1860 1861 1866
in the parent-species, may become, by 1859
to a remote progenitor, may have become, through 1869 1872

principles— namely of each successive modification supervening at a rather late age, and being inherited at a corre- sponding late age— 1860
principles— namely of each successive modification supervening at a rather late age, and being inherited at a corresponding late age— 1859 1861 1866
principles 1869 1872

And the cases just given, more especially that of pigeons, seem to show that the characteristic differences which give value to each breed, and which have been accumulated by mans selection, have not generally first appeared at an early period of life, and have been inherited by the offspring at a corresponding not early period.
And
But
the
cases
case
of the short-faced tumbler, which when twelve hours old had acquired its proper proportions, proves that this is not the universal rule; for here the characteristic differences must either have appeared at an earlier period than usual, or, if not so, the differences must have been inherited, not at the corresponding, but at
a very
an
earlier age.
Now let us apply these facts and the above two principles— which latter, though not proved true, can be shown to be in some degree probable— to species in a state of nature. Let us take a
group
genus
of birds, descended on my theory from some one parent-species, and of which the several new species have become modified through natural selection in accordance with their diverse habits. Then, from the many slight successive
steps of
steps of
variations
variation
having supervened at a rather late age, and having been inherited at a corresponding age, the young of the new species of our supposed genus will manifestly tend to resemble each other much more closely than do the
adults,—
adults,
just as we have seen
with
in
the
breeds
case
of
the pigeon.
pigeons.
We may extend this view to whole families or even classes. The fore-limbs, for instance, which
once served
served
as legs in the parent-species, may have become, by a long course of modification, adapted in one descendant to act as hands, in another as paddles, in another as wings;
but
and
on the above two principles— namely of each successive modification supervening at a rather late age, and being inherited at a corre- sponding late age—