us_, and the hypothetical _Homo stupidus_, and the known
_Homo neanderthalensis_, and, lastly, proud _Homo sapiens_ himself have
descended. Thus Professor Haeckel is able to make the affirmation, as he
did recently before the International Zoological Congress in Cambridge,
that man's line of descent is now clearly traced, from a stage back in
the Eocene time when our ancestor was not yet more than half arrived to
the ape's estate, down to the time of true human development. "There no
longer exists," he says, "a 'missing link.' The phyletic continuity
of the primate stem, from the oldest lemurs down to man himself, is an
historical fact."

It should, perhaps, be added that the force of this rather startling
conclusion rests by no means exclusively upon the finding of
_pithecanthropus_ and the other fossils, nor indeed upon any
paleontological evidence whatever. These, of course, furnish data of
a very tangible and convincing kind; but the evidence in its totality
includes also a host of data from the realms of embryology and
comparative anatomy--data which, as already suggested, enabled Professor
Haeckel to predicate the existence of _pithecanthropus_ long in advance
of his actual discovery. Whether the more remote gaps in the chain of
man's ancestry will be bridged in a manner similarly in accord with
Professor Haeckel's predications, it remains for future discoveries
of zoologist and paleontologist to determine. In any event, the recent
findings have added an increment of glory to that philosophical zoology
of which Professor Haeckel is the greatest living exponent.

This tracing of genealogies is doubtless the most spectacular feature of
the new zoology, yet it must be clear that the establishment of lines
of evolution is at best merely a preparation for the all-important
question, Why have these creatures, man included, evolved at all? That
question goes to the heart of the new zoological philosophy. A partial
answer was, of course, given by Darwin in his great doctrine of natural
selection. But this doctrine, while explaining the preservation of
favorable variations, made no attempt to account for the variations
themselves. Professor Haeckel's contribution to the subject consisted in
the revival of the doctrine of Lamarck, that individual variations, in
response to environmental influences, are transmitted to the offspring,
and thus furnish the material upon which, applying Darwin's principle,
evolution may proceed