ese fishes, which preceded the appearance of
reptiles, present a combination of ichthyic and reptilian characters not
to be found in the true members of this class, which form its bulk at
present. The Pterodactyles, which preceded the class of birds, and the
Ichthyosauri, which preceded the Cetaeca, are other examples of such
prophetic types."[a]

[Footnote a: Agassiz, _Contributions: Essay on Classification_, p.
117, where, we may be permitted to note, the word "Crustacea" is by a
typographical error printed in place of _Cetacea_.]

Now these reptile-like fishes, of which gar-pikes are the living
representatives, though of earlier appearance, are admittedly of higher
rank than common fishes. They dominated until reptiles appeared, when
they mostly gave place to--or, as the derivationists will insist, were
resolved by divergent variation and natural selection into--common
fishes, destitute of reptilian characters, and saurian reptiles, the
intermediate grades, which, according to a familiar piscine saying,
are "neither fish, flesh, nor good red-herring," being eliminated and
extinguished by natural consequence of the struggle for existence which
Darwin so aptly portrays. And so, perhaps, of the other prophetic types.
Here type and antitype correspond. If these are true prophecies, we need
not wonder that some who read them in Agassiz's book will read their
fulfilment in Darwin's.

Note also, in tins connection, that, along with a wonderful persistence
of type, with change of species, genera, orders, etc., from formation to
formation, no species and no higher group which has once unequivocally
died out ever afterwards reappears. Why is this, but that the link of
generation has been sundered? Why, on the hypothesis of independent
originations, were not failing species re-created, either identically or
with a difference, in regions eminently adapted to their well-being? To
take a striking case. That no part of the world now offers more suitable
conditions for wild horses and cattle than the Pampas and other plains
of South America is shown by the facility with which they have there run
wild and enormously multiplied, since introduced from the Old World not
long ago. There was no wild American stock. Yet in the times of the
Mastodon and Megatherium, at the dawn of the present period, wild
horses and cattle--the former certainly very much like the existing
horse--roamed over those plains in abundance. On the principle of