oologist may
be buried there, till future revolutions may raise them in turn
above the water, to afford materials for the study of whatever
race of intelligent beings may then have succeeded us. These
considerations must lead us to the conclusion that our knowledge
of the whole series of the former inhabitants of the earth is
necessarily most imperfect and fragmentary--as much as our
knowledge of the present organic world would be, were we forced to
make our collections and observations only in spots equally
limited in area and in number with those actually laid open for
the collection of fossils.... The hypothesis of Prof. Forbes is
essentially one that assumes to a great extent the _completeness_
of our knowledge of the _whole series_ of organic beings which
have existed on earth.... The hypothesis put forward in this paper
depends in no degree upon the completeness of our knowledge of the
former condition of the organic world, but takes what facts we
have as fragments of a vast whole, and deduces from them something
of the nature and proportion of that whole which we can never know
in detail....

Another important series of facts, quite in accordance with, and
even necessary deductions from, the law now developed, are those
of _rudimentary organs_. That these really do exist, and in most
cases have no special function in the animal economy, is admitted
by the first authorities in comparative anatomy. The minute limbs
hidden beneath the skin in many of the snake-like lizards, the
anal hooks of the boa constrictor, the complete series of jointed
finger-bones in the paddle of the manatee and the whale, are a few
of the most familiar instances. In botany a similar class of facts
has been long recognised. Abortive stamens, rudimentary floral
envelope and undeveloped carpels are of the most frequent
occurrence. To every thoughtful naturalist the question must
arise, What are these for? What have they to do with the great
laws of creation? Do they not teach us something of the system of
nature? If each species has been created independently, and
without any necessary relation with pre-existing species, what do
these rudiments, these apparent imperfections, mean? There must be
a cause for them; they must be the necessary result of some great
natural law. Now, if ... the great la