At first sight it may seem unaccountable that a race of such extremely low intellect should be able to assert their supremacy in this way over the intruding Malayans, assumed to be so much their superiors in physical and mental qualities. But it has to be considered that the invasions took place in very remote times, ages before the appearance on the scene of the semi-civilised Muhammadan Malays of history. Whether of Indonesian or of what is called "Malay" stock, the intruders were rude Oceanic peoples, who in the prehistoric period, prior to the spread of civilising Hindu or Moslem influences in Malaysia, had scarcely advanced in general culture much beyond the indigenous Papuan and Negrito populations of that region. Even at present the Gaddanes, Itaves, Igorrotes, and others of Luzon are mere savages, at the head-hunting stage, quite as wild as, and perhaps even more ferocious than any of the Aetas. Indeed we are told that in some districts the Negrito and Igorrote tribes keep a regular Debtor and Creditor account of heads. Wherever the vendetta still prevails, all alike live in a chronic state of tribal warfare; periodical head-hunting expeditions are organised by the young men, to present the bride's father with as many grim trophies as possible in proof of their prowess, the victims being usually taken by surprise and stricken down with barbarous weapons, such as a long spear with tridented tips, or darts and arrows carrying at the point two rows of teeth made of flint or sea-shells. To avoid these attacks some, like the Central Sudanese Negroes, live in cabins on high posts or trees 60 to 70 feet from the ground, and defend themselves by showering stones on the marauders. A physical peculiarity of the full-blood Negritoes, noticed by J. Montano[362], is the large, clumsy foot, turned slightly inwards, a trait characteristic also of the African Negrilloes; but in the Aeta the effect is exaggerated by the abnormal divergence of the great toe, as amongst the Annamese. The presence of a pygmy element in the population of New Guinea had long been suspected, but the actual existence of a pygmy people was first discovered by the British Ornithologists' Union Expedition, 1910, at the source of the Mimika river in the Nassau range[363].