would have become firmly established, and it would be confirmed, although it could not be originated, by the idea that, as the wife may not be faithful to her husband, there is more certainty about maternity than paternity. The fact that a man’s heirs are usually his sister’s children, shows that consanguinity is of great importance in the eyes of uncultured peoples, and what has been advanced is quite sufficient to account for that fact without assuming the existence of a state of promiscuity in the relations between the sexes. Such a state is not consistent with the abhorrence which even savages show to the marriage of persons of near blood relationship, and it has no support at all in the observed phenomena of savage life. The _punalua_ custom of the Polynesian Islanders, which has its counterpart among the Todas of the Neilgherries, and traces of which may perhaps be found, on the one hand, in the fraternal polyandry of the Tibetans, and, on the other hand, in the sororal polygamy of the North American aborigines, is neither promiscuous nor incestuous in the proper sense of these words. The possession by several brothers of wives in common, who may themselves be sisters, or by several sisters of husbands in common, who may be brothers, may, as I have elsewhere suggested, have originally been due to the feeling that marriage has a spiritual as well as a physical significance. Punalua was really an application of the idea of brotherhood to marriage, and it is not surprising that, among uncultured peoples, the having wives or husbands in common should be considered a high mark of friendship.