the radius and reduction of
the ulna, until the former alone remained entire and effective; third,
a shortening of all the carpal bones and enlargement of the median ones,
insuring a firmer wrist; fourth, an increase of size of the third digit,
at the expense of those of each side, until the former alone supported
the limb.
"Such is, in brief, a general outline of the more marked changes that
seemed to have produced in America the highly specialized modern Equus
from his diminutive four-toed predecessor, the eocene Orohippus. The
line of descent appears to have been direct, and the remains now known
supply every important intermediate form. It is, of course, impossible
to say with certainty through which of the three-toed genera of the
pliocene that lived together the succession came. It is not impossible
that the latter species, which appear generically identical, are the
descendants of more distinct pliocene types, as the persistent tendency
in all the earlier forms was in the same direction. Considering the
remarkable development of the group through the tertiary period, and
its existence even later, it seems very strange that none of the species
should have survived, and that we are indebted for our present horse to
the Old World."(7)
PALEONTOLOGY OF EVOLUTION
These and such-like revelations have come to light in our own time--are,
indeed, still being disclosed. Needless to say, no index of any sort now
attempts to conceal them; yet something has been accomplished towards
the same end by the publication of the discoveries in Smithsonian
bulletins and in technical memoirs of government surveys. Fortunately,
however, the results have been rescued from that partial oblivion by
such interpreters as Professors Huxley and Cope, so the unscientific
public has been allowed to gain at least an inkling of the wonderful
progress of paleontology in our generation.
The writings of Huxley in particular epitomize the record. In 1862 he
admitted candidly that the paleontological record as then known, so far
as it bears on the doctrine of progressive development, negatives
that doctrine. In 1870 he was able to "soften somewhat the Brutus-like
severity" of his former verdict, and to assert that the results of
recent researches seem "to leave a clear balance in favor of the
doctrine of the evolution of living forms one from another." Six years
later, when reviewing the work of Marsh in America and of Gaudry
in Pikermi, he d
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