lurian epoch, we may feel certain that the ordinary succession by
generation has never once been broken, and that no cataclysm has desolated
the whole world. Hence we may look with some confidence to a secure future
of equally inappreciable length. And as natural selection works {490}
solely by and for the good of each being, all corporeal and mental
endowments will tend to progress towards perfection.

It is interesting to contemplate an entangled bank, clothed with many
plants of many kinds, with birds singing on the bushes, with various
insects flitting about, and with worms crawling through the damp earth, and
to reflect that these elaborately constructed forms, so different from each
other, and dependent on each other in so complex a manner, have all been
produced by laws acting around us. These laws, taken in the largest sense,
being Growth with Reproduction; Inheritance which is almost implied by
reproduction; Variability from the indirect and direct action of the
external conditions of life, and from use and disuse; a Ratio of Increase
so high as to lead to a Struggle for Life, and as a consequence to Natural
Selection, entailing Divergence of Character and the Extinction of
less-improved forms. Thus, from the war of nature, from famine and death,
the most exalted object which we are capable of conceiving, namely, the
production of the higher animals, directly follows. There is grandeur in
this view of life, with its several powers, having been originally breathed
by the Creator into a few forms or into one; and that, whilst this planet
has gone cycling on according to the fixed law of gravity, from so simple a
beginning endless forms most beautiful and most wonderful have been, and
are being, evolved.

* * * * *

{491}

INDEX.

A.

Aberrant groups, 429.
Abyssinia, plants of, 375.
Acclimatisation, 139.
Affinities of extinct species, 329.
---- of organic beings, 411.
Agassiz on Amblyopsis, 139.
---- on groups of species suddenly appearing, 302, 305.
---- on embryological succession, 338.
---- on the glacial period, 366.
---- on embryological characters, 418.
---- on the embryos of vertebrata, 439.
---- on parallelism of embryological development and geological
succession, 449.
Algae of New Zealand, 376.
Alligators, males, fighting, 88.
Amblyopsis, blind fish, 139.
America, North, productions allied to those of Europe, 3