_'Systematische Phylogenie,' § 386._
_Perissodactyla_ _Homo_ _Carnivora_
| (_Litopterna_) | | _Pinnipedia_
| | | | |
+-------+ _Anthropoidae_ +------+
_Artiodactyla_ | | |
| | | _Carnassia_
+----------+ _Catarhinæ_ |
| | _Chiroptera_ |
_Proboscidea_ | | | _Insectivora_ |
| | _Platyrhinæ_ | | |
(_Amblypoda_) | | | | +-------+
| | | | | | _Rodentia_
+-------+ | _Simiæ_ +-------+ |
| | | | (_Tillodontia_)
+--+ | | |
_Cetacea_ | | | _Trogontia_
| _Sirenia_ | _Lemures_ _*Ictopsales*_ | _Edentata_
| | | | | | |
_Cetomorpha_ | _Hyracoidea_ | | _*Esthonychales*_
| | | | | |
+---_?_---+------+ | | |
| _*Lemuravidæ*_ | |
_*Condylarthrales*_ | +-------+ |
| | | |
+--------Eutheria s. Placentalia------------------+
|
| _Marsupialia polyprotodontia_
_Marsupialia diprotodontia_ | |
| | |
+-------------Metatheria--------------+
|
| _Monotremata_
| | (_Allotheria_)
| | |
| +-----------------+
| |
Prototheria-----+
|
|
_*Hypotheria s.*_ _*Promammalia*_
_Names in brackets indicate extinct groups.
Names *underlined* indicate hypothetical groups or combinations._
22. Stage of _Simiæ_. Orbit completely separated from the temporal
fossa by an inward extension of the frontal and malar bones meeting the
alisphenoid. Placenta consolidated into a disc, and with a maternal
deciduous portion. Mammæ pectoral only. The dental formula is 2.1.3.3.
All the fingers and toes are protected by flat nails. The tail is long.
The American prehensile-tailed monkeys are a lower side-branch.
23. Stage of _Catarrhinæ Cercopithecidæ_. The dental formula is
2.1.2.3, owing to the loss of one pair of premolars in each jaw.
The frontal and alisphenoid bones are in contact, separating the
parietal from the malar bone; this feature is correlated with the
enlarged brain. The internarial septum is narrow, and the nostrils
look forwards and downwards instead of sidewards--hence the term
'Catarrhinæ.' The external auditory meatus is long and bony. The tail
is long, with the exception of _Macacus inuus_. The body is covered
with a thick coat of furry hair. Catarrhine monkeys have existed, we
know with certainty, since the Miocene.
24. Stage of _Catarrhinæ Anthropoidæ_, or _Apes_. Now represented by
the large apes--namely, the Hylobates or gibbon of South-Eastern Asia,
_Simia satyrus_, the orang-utan of Sumatra and Borneo, _Troglodytes
gorilla_, _T. niger_ and _T. calvus_, the gorilla and the chimpanzees
from Western Equatorial Africa. Of fossils are to be mentioned
Pliopithecus and Dryopithecus from European Miocene, and _Troglodytes
sivalensis_ from the Pliocene of the Punjaub. The tail is reduced
to a few caudal vertebræ, which are transformed into a coccyx, not
visible externally; but in the embryos of apes and man the tail is
still a conspicuous feature. The walk is semierect; in adaptation
to the prevailing arboreal life, the arms are longer than the legs.
The hair of the body is considerably more scanty than in the tailed
monkeys. _Troglodytes calvus_, a species or variety of chimpanzee, is
bald-headed. None of the recent genera of apes can lay claim to a place
in the ancestry of mankind.
25. Stage of _Pithecanthropi_. Hitherto the only known representative
is _Pithecanthropus erectus_, from the Upper Pliocene of Java. In
adaptation to a more erect gait, the legs have become stronger and the
hind-hand has been turned into a flat-soled walking 'foot.' The brain
is considerably enlarged. Presumably it is still devoid of so-called
articulate speech; this is indicated by the fact that children have
to learn the language of their parents, and by the circumstance that
comparative philology declares it impossible to reduce the chief human
languages to anything like one common origin.
26. _Man._ Known with certainty to have existed as an implement-using
creature in the last Glacial epoch. His probable origin cannot,
therefore, have been later than the beginning of the Plistocene. The
place of origin was probably somewhere in Southern Asia.
Whilst we have to admit that there are great defects in the older
(invertebrate) portion of our pedigree, we have all the more reason to
be satisfied with the positive results of our investigation of the more
recent (vertebrate) part of it. All modern researches have confirmed
the views of Lamarck, Darwin, and Huxley, and they allow of no doubt
that the nearest vertebrate ancestors of mankind were a series of
Tertiary Primates.
Particularly valuable are the admirable attempts of the two zoologists,
Paul and Fritz Sarasin,[22] to throw light upon the human phylogeny by
painstaking comparison of all the skeletal parts of man with those of
the anthropoid apes. They have shown that among the lower races of man
the primitive Veddahs of Ceylon approach the apes most nearly, and that
among the latter the chimpanzee stands nearest to man.
[22] 'Ergebnisse naturwissenschaftlicher Forschungen auf Ceylon,' vols.
4 and 5. (With an atlas of 84 plates; 1893.)
The direct descent of man from some extinct ape-like form is now beyond
doubt, and admits of being traced much more clearly than the origin
of many another mammalian order. The pedigrees of the Elephants, the
Sirenia, the Cetacea, and, above all, of the Edentata, for example,
are much more obscure and difficult to explain. In many parts of their
organization--for example, in the number and structure of his five
digits and toes--man and monkeys have remained much more primitive than
most of the Ungulata.
The immense significance of this positive knowledge of the origin of
man from some Primate does not require to be enforced. Its bearing
upon the highest questions of philosophy cannot be exaggerated. Among
modern philosophers no one has perceived this more deeply than Herbert
Spencer.[23] He is one of those older thinkers who before Darwin were
convinced that the theory of development is the only way to solve
the 'enigma of the world.' Spencer is also the champion of those
evolutionists who lay the greatest weight upon _progressive heredity_,
or the much combated _heredity of acquired characters_. From the first
he has severely attacked and criticised the theories of Weismann, who
denies this most important factor of phylogeny, and would explain
the whole of transformism by the 'all-sufficiency of selection.' In
England the theories of Weismann were received with enthusiastic
acclamation, much more so than on the Continent, and they were called
'Neo-Darwinism,' in opposition to the older conception of Evolution,
or 'Neo-Lamarckism.' Neither of those expressions is correct. Darwin
himself was convinced of the fundamental importance of progressive
heredity quite as much as his great predecessor Lamarck; as were also
Huxley and Spencer.
[23] 'Principles of Biology': 'The Factors of Organic Evolution'; 'The
Inadequacy of Natural Selection.'
Three times I had the good fortune to visit Darwin at Down, and on each
occasion we discussed this fundamental question in complete harmony.
I agree with Spencer in the conviction that progressive heredity is
an indispensable factor in every true monistic theory of Evolution,
and that it is one of its most important elements. If one denies with
Weismann the heredity of acquired characters, then it becomes necessary
to have recourse to purely mystical qualities of germ-plasm. I am of
the opinion of Spencer, that in that case it would be better to accept
a mysterious creation of all the various species as described in the
Mosaic account.
If we look at the results of modern anthropogeny from the highest point
of view, and compare all its empirical arguments, we are justified in
affirming that _the descent of man from an extinct Tertiary series of
Primates is not a vague hypothesis, but an historical fact_.
Of course, this fact cannot be proved _exactly_. We cannot explain all
the innumerable physical and chemical processes, all the physiological
mutations, which have led during untold millions of years from the
simplest Monera and from the unicellular Protista upwards to the
chimpanzee and to man. But the same consideration applies to all
historical facts. We all believe that Aristotle, Cæsar, and King Alfred
did live; but it is impossible to give a proof within the meaning of
modern exact science. We believe firmly in the former existence of
these and other great heroes of thought, because we know well the works
they have left behind them, and we see their effects in the history
of human culture. These indirect arguments do not furnish stronger
evidence than those of our history as vertebrates. We know of many
Jurassic mammals only a single bone, the under jaw. We all believe that
these mammals possessed also an upper jaw, a skull, and other bones.
But the so-called 'exact school,' which regards the transformation of
species as a hypothesis not proven, must suppose that the mandibula was
the only bone in the body of these curious animals.
Looking forward to the twentieth century, I am convinced that it will
universally accept our theory of descent, and that future science
will regard it as the greatest advance made in our time. I have no
doubt that the influence of the study of anthropogeny upon all other
branches of science will be fruitful and auspicious. The work done in
the present century by Lamarck and Darwin will in all future times be
considered one of the greatest conquests made by thinking man.