to render ever more complete and conclusive the evidence for the doctrine of descent.

The testimony of paleontology as to the origin of man, although much less complete than could be desired, points clearly to the descent of man from some apelike ancestor. No competent morphologist supposes that man was derived from any of the existing species of apes. Man and the apes are considered as representing the ends of a group of branches which lead back to a common stem. People who object to being descended from monkeys may possibly derive some consolation by considering these animals as second cousins instead of progenitors. There cannot be the least doubt, however, that man, apes, and monkeys all belong to the natural order of Primates. Structurally, as Huxley conclusively proved, man differs less from the higher anthropoid apes than the latter differ from the more primitive members of the monkey tribe. But just how man is related genealogically to the various other members of his order is still an unsettled problem.

Remains of the most primitive group of monkeys, the lemurs, are found as far back as the Eocene. In the Oligocene, remains of an anthropoid related to the modern gibbon have been found in Egypt. Other apes resembling the anthropoids occur in the middle Miocene, while during the Pliocene the anthropoids are represented by forms that more or less closely resemble the existing species of chimpanzee, orang-utan, and gorilla. The anthropoids died out relatively early in Europe, but they have persisted in Africa and parts of southern Asia.

In 1894, the Dutch surgeon, Dubois, described parts of the skeleton of an apelike human being, Pithecanthropus erectus, which was discovered in the late Pliocene, or early Pleistocene deposits of Java. Of the head only the upper part of the skull and two molar teeth were preserved. The forehead was low and flattened, and had a projecting brow. The cranial capacity was about two-thirds that of an average human skull. The teeth are described as being more human than apelike. A single femur, which was found about fifty feet from the rest of the

skeleton, indicates, if it really belongs to the same skeleton, that the Pithecanthropus must have been nearly as tall as the average European. What is known of Pithecanthropus indicates that it represents a very primitive type of human being, or a very human type of ape, whichever we may be pleased to call it.

A

C

Next in age to Pithecanthropus (which is supposed to date back nearly 500,000 years) comes the Heidelberg man, of whom only a single lower jaw was discovered about seventy-nine feet below the surface near Heidelberg, Germany, with the remains of several extinct animals. The teeth are described as distinctly human, but primitive; but the jaw is unusually massive and apelike, and devoid of the distinctively human projecting chin (Fig. 215C).

Another primitive human type is the Piltdown man discovered in Sussex near the river Thames. The cranium was of fair size, but if the lower jaw found near by really belongs to it and not, as has been suggested, to a chimpanzee, the Piltdown remains probably belonged to a creature sufficiently below present-day man to justify the institution of the separate generic name of Eoanthropus (literally "dawn man"). According to Prof. Elliot Smith, the claim that the lower jaw belonged to a chimpanzee “ignores not merely the improbability of such a chance association in the same spot of the remains of a hitherto unknown man-like Ape, and an equally unknown ape-like Man, one of which left his skull without the jaw, and the other the jaw with

FIG. 214-A, skull of the Piltdown man; B, skull of a Neanderthal man from La-Chapelleaux-Saints; C, modern human skull. (By permission of the Geological Society of London.)

out the skull, but also the large series of anatomical peculiarities of the jaw and teeth which prove the jaw to be, not a chimpanzee's, but that of a primitive human being-no doubt a part of the same individual whose skull was

deposited alongside it."

The Rhodesian skull found a few years ago in South Africa shows also a well developed cranium, but this is associated with facial peculiarities which indicate that the face belonged to a type "more primitive and brutal than any other human being, living or extinct, that is at present known" (Smith). It is apparently impossible to specify, with any degree of accuracy, the precise period of time to which either the Piltdown or the Rhodesian skull belongs.

The celebrated Neanderthal skull belonged to a race of primitive men with a low, flattened cranium, short flexed legs, and short, thick set body, who ranged over a considerable part of Europe. Homo neanderthalensis was probably not a particularly prepossessing species of his genus. According to Osborn, "the cranium is dolichocephalic, with prominent supraorbital processes and relatively short and broad nose, weak lower jaw, lack

ing the prominent chin process. These characters, as well as the posterior position of the foramen magnum and the form of the palate, are distinctively simian or prehuman.'

Neanderthal man was succeeded by the Crô-Magnons, who

were a fine, tall people with high foreheads and well developed crania. Their remains, together with specimens of their handiwork, are found widely scattered over Europe and parts of western Asia. The Crô-Magnons were followed by several other races whose history has as yet been very imperfectly traced.

G. THE EVIDENCE FROM GEOGRAPHICAL DISTRIBUTION

It is perhaps not immediately evident that the study of the way in which species of plants and animals are distributed over the surface of the globe, should afford a most excellent means of judging whether or not they arose by a process of evolution. The significance of paleontology for evolutionary theory is obvious enough. The distribution of organisms in time, as we have seen, is in close agreement with what would be expected according to the theory of descent. But the distribution of organisms in space is no less important in relation to evolution, and its verdict no less crucial.

We may perhaps make this fact more obvious by employing an illustration from an imaginary case. Let us suppose that during the history of the earth's surface only a single large island should have arisen out of the sea. This island, we may suppose, was peopled by organisms which left their original aquatic habitat and gradually became adapted to a terrestrial mode of life. In accordance with the doctrine of evolution let us further suppose that these original inhabitants gave rise through descent to a diversified fauna and flora, the species of which became scattered over its surface and settled down in situations to which they were peculiarly fitted. We may assume also that our island was the scene of many geological changes; mountain chains were erupted at various periods, dividing it into regions across which most species were unable to migrate. Through the subsidence of certain areas, parts of the island were cut off from the mainland at different stages of its history, thereby forming smaller islands whose inhabitants were isolated for varying periods of time. Remember that, during all this time, life was evolving, and species were branching and rebranching from the

original ancestral forms and migrating where they could. What kind of a picture would the distribution of species on our island present?

If a naturalist (who, we may assume, is a geologist as well as a botanist and zoölogist) should visit this region and study its fauna and flora in order to find some clue as to their possible evolution, what sort of relations would he look for? Among other things he would certainly study the relation of barriers to the distribution of the species which they separate. He would expect to find that those regions which had been separated for the longest time would have the most widely different forms of life. If he studied the geological history of the outlying islands and ascertained the relative periods at which they were cut off from the mainland, he would look for the greatest differences in the life of those which had been first formed. Our naturalist would doubtless anticipate that the area occupied by a species would be closely related to its means of dispersal. He might look for slow-burrowing moles, for instance, to be quite restricted in the range of their species, while the species of ferns or fungi, whose spores could be easily carried to great distances by the wind, would be found in almost every locality suitable for their growth. He would also probably infer that closely related species would exhibit a tendency to cluster together more or less in the same general area. And since, according to the theory of evolution, present species are the descendants of previously existing ones, our naturalist would seek in recent deposits forms similar to those now living in the same region.

All of these relations which the naturalist would look for would inevitably exist in our island area if its fauna and flora had arisen by a process of evolution. Consequently if the naturalist discovered that these relations actually existed, he would be pretty sure that evolution had taken place. If, on the other hand, the various species had been created, there would be no assignable reason why most of these relations should be found.

Our illustration ought to make it apparent, I think, that a study of the distribution of species over the earth should afford