, they must be held to have had a widely different parentage.
Now, in all such cases where there is thus what is called an analogous
(or adaptive) resemblance, as distinguished from what is called an
homologous (or anatomical) resemblance--in all such cases it is
observable that the similarities do not extend further into the
structure of the parts than it is necessary that they should extend, in
order that the structures should both perform the same functions. The
whole anatomy of the paddles of a whale is quite unlike that of the fins
of a fish--being, in fact, that of the fore-limb of a mammal. The
change, therefore, which the fore-limb has here undergone to suit it to
the aquatic habits of this mammal, is no greater than was required for
that purpose: the change has not extended to any one feature of
_anatomical_ significance. This, of course, is what we should expect on
the theory of descent with modification of ancestral characters; but on
the theory of special creation it is not intelligible why there should
always be so marked a distinction between resemblances as analogical or
adaptive, and resemblances as homological or of meaning in reference to
a natural classification. To take another and more detailed instance,
the Tasmanian wolf is an animal separated from true wolves in a natural
system of classification. Yet its jaws and teeth bear a strong general
resemblance to those of all the dog tribe, although there are
differences of anatomical detail. In particular, while the dogs all have
on each side of the upper jaw four pre-molars and two molars, the
Tasmanian wolf has three pre-molars and four molars. Now there is no
reason, so far as their common function of dealing with flesh is
concerned, why the teeth of the Tasmanian wolf should not have resembled
homologically as well as analogically the teeth of a true wolf; and
therefore we cannot assign any intelligible reason why, if all the
species of the dog genus were separately created with one pattern of
teeth, the unallied Tasmanian wolf should have been furnished with what
is practically the same pattern from a functional point of view, while
differing from a structural point of view. But, of course, on the theory
of descent with modification, we can well understand why similarities of
habit should have led to similarities of structural appearance of an
adaptive kind in different lines of descent, without there being any
trace of such real or anatomical simil