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 EVOLUTION

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EVOLUTION

Skill (190S)

human, and have given rise to renewed interest through the valuable discoveries made in Krapina. The Neandertal skull itself serves as a type which, owing to the low, receding forehead and the strongly developed supra-orliital ridges, appears to be very primitive, though no one knows the actual geological conditions of the place where it was originally deposi- ted. We pass over the fact that twenty scientists have expressed twelve tlifferent opinions on this mys- terious crHiiium, and confine oiu'selves to the latest opinion of Scliwall;)e, who says that the Neandertal cranium exhibits forms which are never found in either a normal or a pathologically altered Homo sapiens, whetlier Negro, European, or Australian, and yet at the same time the skull does exhibit human charac- teristics. In a word, the Neandertal skull does not belong to any variety of Homo sapiens. Kohl- brugge very apt- ly compares Schwalbe's hy- pothesis to an upturned pyra- mid balancing on a fine point, since a single Australian or Negroid skull which may be found to agree with the Nean- dertal skull suf- fices to over- throw the hypothesis. Such a skull has not as yet been found, but there are other factors which suf- fice to shake Schwalbe's hypothesis. These have ref- erence to the other diluvial bone remains of Homo primigenius, amongst others to the petrified Gibraltar skull, to two molar teeth from the Tauliach cave, to the two fragments of a skull from the mammoth caves of Spy, and the jawbones from La Naulette, Schipka, Ochos, ami. finally, to considerable remains of bones, such as fragments of skulls, lower jawbones, pelvic bones, thigh and shin bones, from a cave near Krapina in Croatia. To these must be added the " Moustier skull" which was dug up in August, 1908, in V(^zere- tal (Dordogne). All these fragments possess fairly uniform characteristics. Especially worthy of note are, above all, the cranium with its prominent supra- orbital ridges and receding forehead. These quali- ties, however, are not infrequently found in men of the present day. Australians exhibit here and there even the genuine supra-orbital ridges (Gorjanowic-Kram- berger). It cannot be clearly decided whether we are dealing with purely individual characteristics or with peculiarities which would justify us in classifying the Krapina fragments as belonging to a special race. But this much is clear, that the formation of the skull and the degree of civilization of that race are quite sullicieiit to permit of our designating Homo primi- grniiix not as a species of itself, but merely as a local sub-division of the Homo sapiens. The Galley Hill skull, from England, which is still older than the Krapina bones, points to the same conclusion and cor- responds with the more recent skulls of post-diluvial man. Hence, to sum up, we may affirm that we are acquainted with no records of Tertiary man, that the most ancient remains of the Quaternary belong to the Galley Hill man, whose skull worthily represents Homo sapiens. The same is to be said of the oldest traces of civilization as yet known to us.

PaUrontology, therefore, can assert nothing what- ever of a development of the body of man from the animal. It may be added that Haeckel's curious " Progonotaxis", or genealogy of man, is a pure fiction. It consists of thirty stages, beginning with the " mon-

ers" and ending with homo loquax. The first fifteen stages have no fossil representatives. As to the rest, we may concede that many of these groups actually exist, but we do not see a single argument of any probability for Haeckel's assertion that these groups are genetically related. As to the age of the human species, no assertion can be made with any degree of certainty; thus far there are no indications whatever that would justify an estimate of more than 10,000 years. Still less are we enabled to say anything defi- nite as to the probable age of life. The numbers given by different authors vary between twenty-four and upwards of one hundred million years. De Vries's calculation is of especial interest because it is based on his (Enothera studies. Mainly to show the superiority of the mutation theory to the selection theory, de Vries assumes that the primrose contains 0000 charac- teristics, and that a "mutation", or acquisition of a new character, takes place after everv 4000 years; so that 4000x6000=24,000,000 ( = Lord Kelvin's average value) woukl represent the biothronic equation, which of course consists of unknown variables only, and rests, moreover, on the unproved assumption that a mutation consists in the acquisition of a new character and that such mutations have really occurred.

IV. Thk Morphological Argument. — (1) In Gen- eral. — The groups and sub-groups of the plant and animal world are built up according to the same funda- mental plan of organization. This important fact, on which all classification rests, is said to be explained by the hypothesis that the different groups (e. g. the vertebrates) have been evolved from forms possessing the peculiarities of the type, while the differences are said to have been brought about by modifications (e. g. adaptation to the environment). The original form or type is imagined to be as primitive as possible, while its modification is said to mark progress, so that those organisms which have the simplest structure are said to correspond to the most ancient forms, the more perfect specialized forms being the most recent.

Are these conclusions well founded? — The plain facts are these: (a) Groups of organisms exhibit simi- lar fundamental forms, which, however, (b) show various differences, so that (c) the groups fall into similar divisions with a more or less perfect tlegree of organization. In the first place it is difficult to untler- stand why the lower organized forms should be histori- cally the older. According to the evidence furnished by palirontology, this is in many instances positively false, anil in no case is it demonstrable, while philo- sophically it is only possible in as far as the simple forms actually possess the peculiarities of their de- scendants at least in some latent condition. Sec- ondly, it is hard to see why similarity of structure should prove common origin. As a matter of fact, pala?ontology knows nothing of common primeval forms; on the contrary, it points to panillcl series whose origins are unknown. It is not improbable, moreover, that resemblances of structure and function in nature frequently represent instances of conver- gence, through which widely different organisms as- sume similar modifications of form under similar con- ditions of life. For example, certain species of the asclepiadacaf (Stapelia), euphorbiaccw (Enpliorbia) , and cactus have, in all probability, acquired their similar fleshy form from the adaptation of leafy forms to the aridity of the locality in which they grew, and only preserved the ilifferent family eluiractcristics in the structure of the flower. The similaritj^ which exists between whales and fishes can be considered merely as an instance of convergence, and no one will assert that the whale has developed from the fish because it happens to be provided with fins. As a matter of fact there arc numberless analogies which no serious stu- dent would ever dream of reducing to a common ori- gin. Take, for example, the cell-<livisioii in plants and animals, the method of fertilization, and other