of the transformation of species.
Against these cases, and against using the palaeontological archives as a
basis for the construction of genealogical trees in general, the weighty
and apparently decisive objection is urged, that nowhere are the soft
parts of the earlier forms of life preserved, and that it is impossible to
establish relationships with any certainty on the basis of hard parts
only, such as bones, teeth and shells. Even Haeckel admits that snails of
very different bodily structure may form very similar and even hardly
distinguishable shells.

Fleischmann further asserts that Haeckel's "fundamental biogenetic law"
has utterly collapsed. "Recapitulation" does not occur. Selenka's figures
of ovum-segmentation show that there are specific differences in the
individual groups. The origin and development of the blastoderm or
germinal disc has nothing to do with recapitulation of the phylogeny. It
is not the case that the embryos of higher vertebrates are
indistinguishable from one another. Even the egg-cell has a specific
character, and is totally different from any unicellular organism at the
Protistan level. The much-cited "gill-clefts" of higher vertebrates in the
embryonic stage are not persistent reminiscences of earlier lower stages;
they are rudiments or primordia shared by all vertebrates, and developing
differently at the different levels; (thus in fishes they become breathing
organs, and in the higher vertebrates they become in part associated with
the organs of hearing, or in part disappear again).

Though Fleischmann's vigorous protest against over-hastiness in
construction and over-confidence on the part of the adherents of the
doctrine of descent is very interesting, and may often be justified in
detail, it is difficult to resist the impression that the wheat has been
rejected with the chaff.(23)

Even a layman may raise the following objections: Admitting that the great
groups of forms cannot be traced back to one another, the palaeontological
record still proves, though it may be only in general outline, that within
each phylum there has been a gradual succession and ascent of forms. How
is the origin of what is new to be accounted for? Without doing violence
to our thinking, without a sort of intellectual autonomy, we cannot rest
content with the mere fact that new elements occur. So, in spite of all
"difficulties," the assumption of _an actual descent_ quietly forces
itself upon us as the