features of nomenclature resembling those of Pentecost.
I must again ask, how are you going to explain the features of the Pentecost system psychologically? What psychological resemblance is there between a grandmother and a sister, between a mother-in-law and a daughter, between a brother-in-law and a grandfather? Apart from some special form of social relationship, there can be no such resemblances. Further, if there were such psychological resemblances, why should we know of their influence on nomenclature only in Pentecost and among the Dieri? The features to be explained are definitely known to exist in only two systems of the world, and it is only among the peoples who use these two systems that we have any evidence of that extraordinary form of marriage of which they would be the natural consequence.
I have now tried to show the dependence of special features of the classificatory system of relationship upon special social conditions. If I have succeeded in this I shall have gone far towards the accomplishment of one of the main purposes of these lectures. They have, however, another purpose, viz., to inquire how far we are justified in inferring the existence of a social institution of which we have no direct evidence when we find features of the nomenclature of relationship which would result from such an institution. I have now