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 |
|