Physically the typical North Pacific tribes are of medium stature, with long arms and short bodies. Among the northern branches the stature averages 1.675 m. (5 ft. 6 in.), the head is very large with an average index of 82.5. The face is very broad, the nose concave or straight, seldom convex, with slight elevation. Among the southern tribes, notably the Kwakiutl, the stature averages 1.645 m. (5 ft. 4-3/4 in.), the cephalic index is 84.5, the face very broad but also of great length, the nose very high, rather narrow and frequently convex. The social relations of these peoples vary from tribe to tribe, but on the whole they fall into a sequence from north to south. In the northern portion descent is matrilineal, but patrilineal in the south. J. G. Frazer does not accept the view of Boas "that the Northern Kwakiutl have borrowed both the rule of maternal descent and the division into totemic clans from their more northerly neighbours of alien stocks; in other words, that totemism and mother-kin have spread southward among a people who had father-kin and no totemic system[819]." He inclines "to the other view, formerly favoured by Boas himself, namely, that the Kwakiutl are in a stage of transition from mother-kin to father-kin[820]." Each village is autonomous and originally may have been restricted to a single totem clan. The population is divided into three ranks, nobles, common people and a low caste consisting of poor people and serfs who cannot participate in the secret societies. In addition there is a totemic grouping. There may be several totemic clans in one village and the same totem may not only occur in every village, but may extend from one tribe to another. This suggests that there were originally two, or in some cases more than two, totemic clans which in process of time became subdivided into sub-clans; these, while retaining the crest of the original clan, acquired fresh ones, and the families contained in each sub-clan may have their special crest or crests in addition. New crests and names are constantly being introduced. Marriage is forbidden between people of the same crest, irrespective of the tribe. The natives according to Boas do not consider themselves descendants from their totem. A wife brings her father's position, crest and privileges as a dower to her husband, who is not allowed to use them himself, but acquires them for the use of his son, in other words this inheritance is in the female line.