Behind them Negroid peoples poured into Africa, apparently in successive waves. Some of them went into the Malay Peninsula, probably generally submerging the Negritos, and reached New Guinea and Australia. Inhabiting a series of islands and other more or less isolated areas, mingling often with Negritos, probably later also more or less with the Malays, they became much modified, and their relations to the African Negroes and to one another are still anything but clear. The Mongoloids pushed eastward. The earliest migrations seem to be those of the Malays, a great, very interesting, and little-known though much-studied group of peoples. They followed the oceanic Negritos along the Malay Peninsula and occupied the great chains of islands stretching through the Indian Ocean and far into the Pacific, through more than ninety degrees of longitude along the equator. But much of this spread is probably of quite recent date. The Mongoloid peoples seem to have passed along the northern front of the Central Asiatic plateau into Siberia, China, and Japan, and to have sent off the great American branch. Even before the Mongols had started on their eastward journey the Caucasians may have turned westward, following the old Negroid route. There was probably also more or less of an eastern dispersal, but we cannot consider the problem of these Oriental Caucasic remnants and traces. The great body went westward. The Hamitic peoples distributed themselves along the southern shore of the Mediterranean, and many may well have occupied a large part of the Sahara region, then a land of watercourses capable of supporting a large population. Behind them came the Semitic folk. Judging from their languages the Hamitic and Semitic peoples seem to have been in contact over a wide area, and for a long space of time. The Semites found a new and permanent home in Arabia, on whose plateaus and surrounding grasslands they increased and multiplied, and sent off fresh waves of migration and conquest in all directions. We have already noticed that our classification of races is based upon a study of recent and still surviving peoples. The very earliest inhabitants of Europe would find no place in it. Probably they long antedated the Hamites. African Negroids and Caucasians came from a common home, and journeyed for a time over a common road, though probably at far different times. It would be strange if the earliest inhabitants of Europe showed no traces of this common home and ancestry. Since the remote period which we are considering Negroes and Caucasians have become widely different, and their racial characters have become clear and sharp. This may not have been altogether the case with the first peoples to arrive in Europe. But attempts to relate the Neanderthal crania with those of modern Australians or Tasmanians, or any existing race, have met with no great success. In regard to these questions we are still in the dark.