In confirmation of this view, let us glance at the classification of varieties, which are
believed | believed 1859 1860 1861 1866 1869 | | known 1872 |
or
known | known 1859 1860 1861 1866 1869 | | believed 1872 |
to
have | have 1859 1860 1861 1866 | | be 1869 1872 |
descended from
one | one 1859 1860 1861 1866 | | a single 1869 1872 |
species. These are grouped under
species, with | species, with 1859 1860 1861 1866 |
| the species, with the 1869 1872 |
sub-varieties under
varieties; and with our domestic productions, | varieties; and with our domestic productions, 1859 1860 1861 1866 |
| the varieties; and in some cases, as with domestic pigeons, 1869 |
| the varieties; and in some cases, as with the domestic pigeon, with 1872 |
several other grades of
difference | difference 1859 1860 1861 1866 1869 | | difference. 1872 |
are | are 1859 1860 1861 1866 1869 | are 1872 |
requisite, | requisite, 1859 1860 1861 1866 | | requisite. 1869 | requisite, 1872 |
as | as 1859 1860 1861 1866 | as 1872 | as 1869 |
we | we 1859 1860 1861 1866 | we 1872 | we 1869 |
have | have 1859 1860 1861 1866 | have 1872 | have 1869 |
seen | seen 1859 1860 1861 1866 | seen 1872 | seen 1869 |
with | with 1859 1860 1861 1866 | with 1872 | with 1869 |
pigeons. | pigeons. 1859 1860 1861 1866 | pigeons. 1872 | pigeons. 1869 |
The origin of the existence of groups subordinate to
groups, | groups, 1859 1860 | | groups 1861 1866 |
is the same with varieties as with species, namely, closeness of descent with various degrees of modification. Nearly the same rules are followed
in classifying varieties, as with | in classifying varieties, as with 1859 1860 1861 1866 |
| as in classifying 1869 1872 |
species. Authors have insisted on the necessity of
classing | classing 1859 1860 1861 1866 | | arranging 1869 1872 |
varieties on a natural instead of an artificial system; we are cautioned, for instance, not to class two varieties of the pine-apple together, merely because their fruit, though the most important part, happens to be nearly identical; no one puts the
swedish | swedish 1859 1860 | | Swedish 1861 1866 1869 1872 |
and common
turnips | turnips 1859 1860 1861 1866 1869 | | turnip 1872 |
together, though the esculent and thickened stems are so similar. Whatever part is found to be most constant, is used in classing varieties: thus the great agriculturist Marshall says the horns are very useful for this purpose with cattle, because they are less variable than the shape or colour of the body, &c.; whereas with sheep the horns are much less serviceable, because less constant. In classing
varieties, | varieties, 1859 1860 1861 1866 1869 | | varieties; 1872 |
I apprehend
if | if 1859 1860 1861 | | that if 1866 1869 1872 |
we had a real pedigree, a genealogical classification would be universally
preferred; | preferred; 1859 1860 1861 1866 1872 | | preferred: 1869 |
and it has been attempted
by | by 1859 1860 1861 1866 | | in 1869 1872 |
some
authors. | authors. 1859 1860 1861 1866 | | cases. 1869 1872 |
For we might feel sure, whether there had been more or less modification,
the | the 1859 1860 1861 1866 1869 | | that the 1872 |
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 | sub-varieties differ from the others 1859 1860 1861 1866 |
| of the sub-varieties differ 1869 1872 |
|