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42 practice were ever sufficiently habitual to become the basis of the system of relationship, we can be confident that it is the former of these two alternatives with which we have to do.

If you are still so under the domination of ideas derived from your own social surroundings that you cannot believe in such a marriage, I would remind you that there is definite evidence from the Banks Islands that men used to hand over wives to their sisters' sons. It is not taking us so much into the unknown as it might appear to suppose that they once also gave their wives to their sons' sons.

I have taken this case somewhat out of its proper place in my argument because the evidence is so closely connected with that by means of which I have shown the relation between features of systems of relationship and peculiar forms of marriage in Melanesia. I have now to return to the more sober task of considering how far we are justified in inferring the former existence of marriage institutions when we find features of systems of relationship of which they would have been the natural consequence. It is evident that, whenever we find such a feature as common nomenclature for a grandmother and a sister or for a cross-cousin and a parent, it should suggest to us the possibility of such marriage regulations as those of Pentecost and the Banks Islands. But such common designations might have arisen in some other way, and in order to establish the existence of such forms of marriage in the past