have been but little modified,
and they yet form a single genus. But this genus, though much isolated,
will still occupy its proper intermediate position; for F originally was
intermediate in character between A and I, and the several genera descended
from these two genera will {422} have inherited to a certain extent their
characters. This natural arrangement is shown, as far as is possible on
paper, in the diagram, but in much too simple a manner. If a branching
diagram had not been used, and only the names of the groups had been
written in a linear series, it would have been still less possible to have
given a natural arrangement; and it is notoriously not possible to
represent in a series, on a flat surface, the affinities which we discover
in nature amongst the beings of the same group. Thus, on the view which I
hold, the natural system is genealogical in its arrangement, like a
pedigree; but the degrees of modification which the different groups have
undergone, have to be expressed by ranking them under different so-called
genera, sub-families, families, sections, orders, and classes.

It may be worth while to illustrate this view of classification, by taking
the case of languages. If we possessed a perfect pedigree of mankind, a
genealogical arrangement of the races of man would afford the best
classification of the various languages now spoken throughout the world;
and if all extinct languages, and all intermediate and slowly changing
dialects, had to be included, such an arrangement would, I think, be the
only possible one. Yet it might be that some very ancient language had
altered little, and had given rise to few new languages, whilst others
(owing to the spreading and subsequent isolation and states of civilisation
of the several races, descended from a common race) had altered much, and
had given rise to many new languages and dialects. The various degrees of
difference in the languages from the same stock, would have to be expressed
by groups subordinate to groups; but the proper or even only possible
arrangement would still be genealogical; and this would be strictly
natural, as {423} it would connect together all languages, extinct and
modern, by the closest affinities, and would give the filiation and origin
of each tongue.

In confirmation of this view, let us glance at the classification of
varieties, which are believed or known to have descended from one species.
These are grouped under species, wit