whether there had been more or less modification,
that the that the 1872 | the 1859 1860 1861 1866 1869 |
principle of inheritance would keep the forms together which were allied in the greatest number of points. In tumbler pigeons, though some sub-varieties differ from the others
in the important character of
the length of the the length of the 1872 |
having a longer 1859 1860 1861 1866 1869 |
beak, yet all are kept together from having the common habit of tumbling; but the short-faced breed has nearly or quite lost this
habit: habit: 1872 | habit; 1859 1860 1861 1866 1869 |
nevertheless, without any reasoning or thinking
on the subject, these tumblers are kept in the same group, because allied in blood and alike in some other respects. ↑1 blocks not present in 1869 1872; present in 1859 1860 1861 1866 | If it could be proved that the Hottentot had descended from the Negro, I think he would be classed under the Negro group, however much he might differ in colour and other important characters from negroes.
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With species in a state of nature, every naturalist has in fact brought descent into his classification; for he includes in his lowest grade, or
that of
....... 1872 | a 1859 1860 1861 1866 | the 1869 |
species, the two sexes; and how enormously these sometimes differ in the most important characters, is known to every naturalist: scarcely a single fact can be predicated in common of the males
and hermaphrodites of certain cirripedes, when adult,
and yet no one dreams of separating them. As soon as the three Orchidean forms, Monachanthus,
Myanthus, and Catasetum, which had previously been ranked as three distinct genera, were known to be sometimes produced on the same plant, they were immediately considered as varieties; and
now I have been able to show that they are
the male, female, and hermaphrodite forms of the same species. The naturalist includes as one species the several
larval stages of the same individual, however much they may differ from each other and from the adult;
as he likewise includes
the so-called alternate generations of Steenstrup, which can only in a technical sense be considered as the same individual. He includes monsters;
he includes
varieties, not solely because they closely resemble
the parent-form, but because they are descended from it. ↑2 blocks not present in 1866 1869 1872; present in 1859 1860 1861 | He who believes that the cowslip is descended from the primrose, or conversely, ranks them together as a single species, and gives a single definition.
As soon as three Orchidean forms (Monochanthus, Myanthus, and Catasetum), which had previously
been ranked as three distinct genera, were known to be sometimes produced on the same spike, they were immediately included as a single species.
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↑5 blocks not present in 1860 1861 1866 1869 1872; present in 1859 | But it may be asked, what ought we to do, if it could be proved that one species of kangaroo had been produced, by a long course of modification, from a bear?
Ought we to rank this one species with bears, and what should we do with the other species?
The supposition is of course preposterous; and I might answer by the
argumentum
ad
hominem
,
and ask what should be done if a perfect kangaroo were seen to come out of the womb of a bear?
According to all analogy, it would be ranked with bears; but then assuredly all the other species of the kangaroo family would have to be classed under the bear genus.
The whole case is preposterous; for where there has been close descent in common, there will certainly be close resemblance or affinity.
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