_, are due to heredity, to the transmission of
characters from one generation to another. They enable us to draw
direct inferences in regard to corresponding structures in the
development of the species (e.g. the chorda or the branchial arches in
all vertebrate embryos). The cenogenetic phenomena, on the other hand,
or the embryonic _variations_, cannot be traced to inheritance from a
mature ancestor, but are due to the adaption of the embryo or the
larva to certain conditions of its individual development (e.g. the
amnion, the allantois, and the vitelline arteries in the embryos of
the higher vertebrates). These cenogenetic phenomena are later
additions; we must not infer from them that there were corresponding
processes in the ancestral history, and hence they are apt to
mislead."

The fundamental importance of these facts of comparative anatomy,
atavism, and the rudimentary organs, was pointed out by Darwin in the
first part of his classic work, _The Descent of Man and Selection in
Relation to Sex_ (1871).[140] In the "General summary and conclusion"
(chap. xxi.) he was able to say, with perfect justice: "He who is not
content to look, like a savage, at the phenomena of nature as
disconnected, cannot any longer believe that man is the work of a
separate act of creation. He will be forced to admit that the close
resemblance of the embryo of man to that, for instance, of a dog--the
construction of his skull, limbs, and whole frame on the same plan
with that of other mammals, independently of the uses to which the
parts may be put--the occasional reappearance of various structures,
for instance of several muscles, which man does not normally possess,
but which are common to the Quadrumana--and a crowd of analogous
facts--all point in the plainest manner to the conclusion that man is
the co-descendant with other mammals of a common progenitor."

These few lines of Darwin's have a greater scientific value than
hundreds of those so-called "anthropological treatises," which give
detailed descriptions of single organs, or mathematical tables with
series of numbers and what are claimed to be "exact analyses," but are
devoid of synoptic conclusions and a philosophical spirit.

Charles Darwin is not generally recognised as a great anthropologist,
nor does the school of modern anthropologists regard him as a leading
authority. In Germany, especially, the great majority of the members
of the anthropological societies took up a