1. It may be a survival of an earlier custom of group-marriage and uterine descent such as is to be found in the Banks Islands, where the entire population is divided into two groups, which we will call X. and O. A man of the X. group must marry an O. woman, and _vice versâ_. The children, following the mother, are O.'s, and are, therefore, kin to their mother's brother rather than to their own father. Their mother's brother, an O., marries an X. woman, whose children are X.'s, and are potential wives to their first cousins; although in the Banks group the blood relationship is not lost sight of, and close marriages are looked upon as improper, whilst in Fiji such a union would be obligatory.[75] The children of two brothers of the X. group, following their mothers, would be O.'s, and therefore forbidden to marry; and so also would be the children of two sisters. Thus far the results of the two customs are the same; but in the Banks group consanguineous marriage is checked by public opinion, which in Fiji favours such marriages. Group-marriage on precisely the same lines has been noticed in Western Equatorial Africa[76] and among the Tinné Indians in North-West America.[77] In Fiji, agnatic has generally taken the place of the uterine descent (although in some parts of Vanualevu traces of the custom still appear to linger), but the existing system of _vasu_, which gives a man extraordinary claims upon his maternal uncle, may be an indication that concubitant marriage is a survival of the more ancient custom. The _vasu_ system is found to some extent among all peoples who trace descent through the mother. Tacitus, speaking of the ancient Germans, says that the tie between the maternal uncle and his nephew was a more sacred bond than the relation of father and son.[78] [Pageheader: ORIGIN OF CONCUBITANCY] 2. It is also possible that concubitant marriage is a relaxation of the stricter prohibition in force amongst the Polynesians. The origin of these prohibitions may, perhaps, be found in some such occurrence as that described in the "Murdu" legend of Australia, quoted by Messrs. Fison and Howitt in _Kamilaroi and Kurnai_-- "After the Creation brothers and sisters and others of the closest kin intermarried promiscuously, until, the evil effects becoming manifest, a council of the chiefs was assembled to consider in what way they might be averted."