viz., the classing of the son's wife with the mother, but it would also account for several features of the Buin system which would otherwise be difficult to understand.
DIAGRAM 5.
| A=b | |||||||||||||||||
| C = d | |||||||||||||||||
| E | F | f | |||||||||||||||
If, as shown in Diagram 5, E marries b, the wife or widow of his father's father, he, who had previously been the elder brother of F and f, now comes to occupy the position of their father's father, while d, the mother of E, will now come to stand to him in the relationship of son's wife.
I need only mention here one of the features of the Buin system which can be accounted for by means of this marriage. The term mamai is used, not only for the elder sister and for the elder brother's wife, but it is also applied to the father's mother; that is, the wife of the elder brother is designated by the same term as the wife of the father's father, exactly as must happen if E marries b, the wife of his father's father. A number of extraordinary features from two Melanesian islands collected by two independent workers fit into a coherent scheme if they have been the result of a marriage in which a man gives one of his wives to his son's son during his life, or in which this woman is taken to wife by her husband's grandson when she becomes a widow. If the
