_progonotaxis_ to our nearest relatives, the anthropoid apes and the
tailed monkeys from which these have descended, but go further back
and find an ancestor in the group of the Lemuridae, and still further
back to the Marsupials and Monotremata. The essential identity of all
the Mammals in point of anatomical structure and embryonic
development--in spite of their astonishing differences in external
appearance and habits of life--is so palpably significant that modern
zoologists are agreed in the hypothesis that they have all sprung from
a common root, and that this root may be sought in the earlier
Palaeozoic Amphibia.

The fundamental importance of this comparative morphology of the
Mammals, as a sound basis of scientific anthropology, was recognised
just before the beginning of the nineteenth century, when Lamarck
first emphasised (1794) the division of the animal kingdom into
Vertebrates and Invertebrates. Even thirteen years earlier (1781),
when Goethe made a close study of the mammal skeleton in the
Anatomical Institute at Jena, he was intensely interested to find that
the composition of the skull was the same in man as in the other
mammals. His discovery of the _os inter-maxillare_ in man (1784),
which was contradicted by most of the anatomists of the time, and his
ingenious "vertebral theory of the skull," were the splendid fruit of
his morphological studies. They remind us how Germany's greatest
philosopher and poet was for many years ardently absorbed in the
comparative anatomy of man and the mammals, and how he divined that
their wonderful identity in structure was no mere superficial
resemblance, but pointed to a deep internal connection. In my
_Generelle Morphologie_ (1866), in which I published the first
attempts to construct phylogenetic trees, I have given a number of
remarkable theses of Goethe, which may be called "phyletic
prophecies." They justify us in regarding him as a precursor of
Darwin.

In the ensuing forty years I have made many conscientious efforts to
penetrate further along that line of anthropological research that was
opened up by Goethe, Lamarck, and Darwin. I have brought together the many
valuable results that have constantly been reached in comparative anatomy,
physiology, ontogeny, and palaeontology, and maintained the effort to
reform the classification of animals and plants in an evolutionary sense.
The first rough drafts of pedigrees that were published in the _Generelle
Morp