they should; no special custom or institution is connected with such a relationship, since in a matrilineal society it is irrelevant. Only a boy and a girl, descendants of a brother and sister respectively, can conclude a marriage which is lawful and which, at the same time, stands out from mere haphazard alliances; for here, as we have seen, a man gives his own kinswoman to his son for a wife. But an important point must here be noted: the man's son has to marry the woman's daughter, and not the man's daughter the woman's son. Only in the former combination do the two people call each other tabugu, a term which implies lawfulness of sexual intercourse. The other couple joined by a dotted line on the diagram (sec. 4) stand in a different relation according to native ideas of kinship (see the discussion of these kinship terms in ch. xiii, sec. 6). A girl calls the son of her father's sister tamagu "my father." Marriage with the real father or with the father's brother is incestuous and strictly tabooed. Marriage with the tama ("father"=father's sister's son) is not incestuous, but it is viewed with disfavour and happens only rarely. Such a marriage offers few inducements. A chief might like his daughter to be married to another chief or to a man of rank in his own family, but she would not thus acquire any specially high or privileged position. On the other hand, as his daughter will have to be supported by the same men who now work for her mother, the chief's wife, he may prefer for his own sake to marry her to a humbler and less exacting person than his heir. It all depends on his relations
