nes, may be given as examples.
Now, if such close relations of homology can be brought about independently
of any but the most remote genetic affinity, it would be rash to affirm
dogmatically that there is any impossibility in the independent origin of
such forms as centetes and solenodon, or of genetically distinct
batrachians, as similar to each other as are some of the frogs of South
America and of Europe. At the same time such phenomena must at present be
considered as very improbable, from the action of ancestral habit, as
before stated.

We have seen, then, that the geographical distribution of animals presents
difficulties, though not insuperable ones, for the Darwinian hypothesis.
If, however, other reasons against it appear of any weight--if, especially,
there is reason to believe that geological time has not been {154}
sufficient for it, then it will be well to bear in mind the facts here
enumerated. These facts, however, are not opposed to the doctrine of
evolution; and if it could be established that closely similar forms had
really arisen in complete independence one of the other, they would rather
tend to strengthen and to support that theory. [Page 155]

* * * * *

CHAPTER VIII.

HOMOLOGIES.

Animals made-up of parts mutually related in various ways.--What
homology is.--Its various kinds.--Serial homology.--Lateral
homology.--Vertical homology.--Mr. Herbert Spencer's explanations.--An
internal power necessary, as shown by facts of comparative anatomy.--Of
teratology.--M. St. Hilaire.--Professor Burt
Wilder.--Foot-wings.--Facts of pathology.--Mr. James Paget.--Dr.
William Budd.--The existence of such an internal power of individual
development diminishes the improbability of an analogous law of
specific origination.

That concrete whole which is spoken of as "an individual" (such, _e.g._, as
a bird or a lobster) is formed of a more or less complex aggregation of
parts which are actually (from whatever cause or causes) grouped, together
in a harmonious interdependency, and which have a multitude of complex
relations amongst themselves.

The mind detects a certain number of these relations as it contemplates the
various component parts of an individual in one or other direction--as it
follows up different lines of thought. These perceived relations, though
subjective, _as relations_, have nevertheless an objective foundatio