clusions, he says: "The hypothesis is indeed flexible. According to
common reasoning, that which shows itself early in the development is an
inheritance of the first progenitors. Therefore the ascidae ought to descend
from the vertebrates, and not the reverse. But it was necessary to show the
descent of the vertebrates from the lower forms. In order to respond to
such a necessity, men sometimes reverse their conclusions. Although
favorably disposed to the doctrine of the transmutation of the animalic
forms, I want a complete proof before I can believe in a transformation of
the vertebrate type into that of the mollusca." Moreover, the zooelogists
Semper and Dohrn find in the embryonic development of the sharks, the
scates, and other cartilaginous fishes, organs which would bring them
rather into a nearer relationship with the ringed worms than with the
crustacea. When, on the other hand, we look around in palaeontology, the
oldest fossil fishes remind us neither of the crustacea nor of the ringed
worms, but of the crabs: a class of animals which lies entirely outside of
Haeckel's stem-line of vertebrates. Also the first appearance of mammalia
does not show transitions. Thus far we have not found in the geological
strata any vestiges of the half-apes, which, according to the hypothesis of
the evolutionists, as a common stem-line for the lines of ape and man
development, once played such an {85} important _role_, and which have
quite numerous representatives.

But the answer which geology gives to our questions as to the probable
confirmation of the evolution theory, naturally becomes most interesting
where the _origin of man_ is treated of. Our attention is, therefore,
especially directed to the most recent formations of the globe which show
us the oldest remains of man. The most instructive are those parts of the
skeleton which allow us to draw the most convincing conclusions as to the
degree of mental development of an individual, namely: the parts of the
skull. Although human bones seem to have been less easily preserved than
those of animals, and are, comparatively speaking, very scarce, especially
more so than prehistoric implements, still there are not wanting such
remains, which go back far beyond historical time. The oldest known skull
is the celebrated one of the Neander cave near Duesseldorf, with its large
vault of the forehead, and its low height. Although Virchow finds on it
evidences of rachitis in youth and