the earth with animal and vegetable life is, that every
change shall be gradual; that no new creature shall be formed widely
differing from anything before existing; that in this, as in everything
else in Nature, there shall be gradation and harmony,--then these
rudimentary organs are necessary, and are an essential part of the
system of Nature. Ere the higher Vertebrata were formed, for instance,
many steps were required, and many organs had to undergo modifications
from the rudimental condition in which only they had as yet existed. We
still see remaining an antitypal sketch of a wing adapted for flight in
the scaly flapper of the penguin, and limbs first concealed beneath the
skin, and then weakly protruding from it, were the necessary gradations
before others should be formed fully adapted for locomotion.[C] Many
more of these modifications should we behold, and more complete series
of them, had we a view of all the forms which have ceased to live. The
great gaps that exist between fishes, reptiles, birds, and mammals would
then, no doubt, be softened down by intermediate groups, and the whole
organic world would be seen to be an unbroken and harmonious system.

+--------------------------------------------------------------+
| [C] The theory of Natural Selection has now taught us that |
| these are not the steps by which limbs have been formed; and |
| that most rudimentary organs have been produced by abortion, |
| owing to disuse, as explained by Mr. Darwin. |
+--------------------------------------------------------------+

_Conclusion._

It has now been shown, though most briefly and imperfectly, how the law
that "_Every species has come into existence coincident both in time and
space with a pre-existing closely allied species_," connects together
and renders intelligible a vast number of independent and hitherto
unexplained facts. The natural system of arrangement of organic beings,
their geographical distribution, their geological sequence, the
phaenomena of representative and substituted groups in all their
modifications, and the most singular peculiarities of anatomical
structure, are all explained and illustrated by it, in perfect
accordance with the vast mass of facts which the researches of modern
naturalists have brought together, and, it is believed, not materially
opposed to any of them. It also claims a superiority over previous
hypotheses, on the ground that it no