the system, the common descent of man and of apes from one common
parent-form, necessarily follows from this inevitable grouping,
and on this proposition only all the general inferences of the
"ape-hypothesis" depend. As to what that common parent-form of men and
apes may have been, very different views might probably be brought on
opposite sides; but any one who knows the collected facts that bear
upon the matter, and estimates them impartially, must, in conclusion,
arrive at the certain conviction that that hypothetical and long-since
extinct parent-form can only have been genuine apes; that is to say,
of the placental mammalian type, such as when we see them now living
before our eyes we unhesitatingly class, on the ground of their
zoological characters, as true apes, in the order of Apes or Primates.

In this, and all other sound phylogenetic hypotheses, we may most
easily attain to a conviction of their truth by taking into
consideration and comparison the other possible hypotheses. But in
fact no single opponent of the ape-hypothesis has been able to combat
it with any other phylogenetic hypothesis that has the faintest
glimmer of probability. Not one opponent has suggested, or can
suggest, any other animal form that can serve as our nearest ancestor
than the ape. No one has ever reproached me by saying that Mother
Nature has endowed me with too little imagination; on the contrary, I
am often accused of having a superfluity of that gift of the gods; but
I have often and repeatedly exerted my imagination to picture to
myself any known or unknown animal-form as the nearest parent-form to
man in the place of the apes, and have always found myself under the
necessity of falling back upon the stock of apes. Let me conceive of
the outward conformation and the internal structure of the nearest
mammalian ancestors of men as I will, I am always forced to
acknowledge that this hypothetical parent-form ranges under the
zoologically-conceived order of apes, and cannot possibly be separated
from the Simiadoe or Primates. If, in spite of this, any one chooses,
out of a "personal crotchet," to accept some other series of unknown
animal ancestors of man that have nothing to do with apes, that is but
a mere empty hypothesis floating in the air. Our ape-hypothesis, on
the other hand, is objectively and thoroughly proved by the essential
agreement of the internal bodily structure of man and of apes, and by
the identity of their emb