The peoples of the north-west coast are most closely allied to the inhabitants of Asia, and are distinguished from the other Amerinds by their lighter skin colour. East of the Rockies and extending over the great plains and into the woodland area there is a group of tall tribes with mesocephalic heads, of whom the Sioux are a typical example. On the east coast in ancient times there was a different type with longer, narrower heads. On the American plateau and extending into central and southern America there is a round-headed type, of short stature and with straight noses, to whom the Maya of ancient times were akin. The Aztecs were more long-headed and their relationship with the more northerly peoples can be traced through some of the inhabitants of northern Mexico to-day.
The ethnology of South America is as yet not fully estab fished, but several types can be distinguished, one akin to the Maya peoples and a type, with a round head and tall stature, in Patagonia, of whom the Fuegians are a branch. Side by side with these straight-haired peoples there exist traces of a curly-haired race, both in ancient deposits and also among some modern tribes. With the exception of the Palaeo-Amerinds the distribution of the straight-haired peoples is continuous, the Bering Strait dividing the Asiatic and American branches.
Woolly-haired Groups—The woolly-haired people have an extremely discontinuous distribution, namely, an eastern habitat which stretches from the continent of Asia to Fiji, and a western, the greater part of Africa. Attempts have been made to bridge this gap. Hiising believes that in ancient times short dark curly haired peoples occurred on the Persian Gulf in localities where negroes are still found. These negroes are, however, the de scendants of imported slaves, and there is no information of a definite character to support Hiising's contention. Some of the jungle tribes of south India are said to have negroid characters, but at present no evidence has been collected to bridge the gap between the two groups, and the characters which link them may be due not to community of ancestry but to the effects of a tropical environment. While the original centre of dispersion of these peoples is at present uncertain, there are almost certainly secondary centres of dispersion in north-east Africa and eastern Asia.
In addition to woolly hair all these peoples have the following characters in common : dark skins sometimes almost black, broad noses, usually a rather small brain in relation to their size, especially among the taller members of the group, with forearms and shins proportionately long. In the skeleton there is a smooth
ness of contour which even in adults often recalls the bony form of a child, and among some members of the group the forehead has that prominent and smooth form which is so characteristic of the infant of our own race. In both eastern and western groups there is a division which includes some very small or pygmy peoples and another of medium or tall-statured tribes.
Eastern Group.—The eastern group may be divided on this basis into the pygmy Negritos and the taller Papuans and Melanesians. The former are all dark-skinned and have heads which are slightly rounded, the cephalic index varying from just under 8o to about 83. There are slight local differences due to the extreme isolation to which these peoples have been subjected. Four separate geographical groups occur, one in the Andaman Islands (the Andamanese), one in the central regions of the Malay Peninsula and eastern Sumatra (the Semang), a third in various parts of the Philippine Is., usually called after a well-known tribe, the Aeta and a fourth group called after a tribe in the west ern mountains of Dutch New Guinea, the Tapiro, who have left traces in other parts of New Guinea and probably also in parts of Melanesia. All these groups are isolated from one another and occupy as it were almost the circumference of a circle. The Andamanese occupy a very special position, both racially and geographically; they have been isolated for a long period and until recently were not in contact with any other race. Such measurements as have been taken indicate that these people are remarkably true to type and show little variation from the average. They are probably the one human group which can be considered a "pure" race.
The Papuans and Melanesians are distinguished from the Negritos by their greater stature and narrower heads; the former probably represent the original stock. At one time they had a wide distribution throughout all Melanesia, probably to Australia, and the extinct Tasmanian aborigines seem to have been a variety of this stock. To-day Papuans are found in New Guinea and in some of the most easterly of the Indian Archipelago islands. They may be distinguished from their kinsfolk by their retreating forehead, prominent brow-ridges and the form of their noses, which are often prominent and rounded, with a down-turned tip.