features of these Melanesian customs if we refused to recognise that the terminology of relationship here “reflects” sociology. This leads me to question for a moment whether it may not be the same with that custom of our own society which Professor Kroeber has taken as his example of the psychological causation of the terminology of relationship. Is it as certain as Professor Kroeber supposes that the classing of the brother-in-law with the brother, or of the sister-in-law with the sister, among ourselves does not reflect sociology? We know that there are social factors at work among us which give to these relationships, and especially to that of wife’s sister, a very great importance. If instead of stating dogmatically that this feature of our own terminology is due to the psychological similarity of the relationships, Professor Kroeber’s mind had been open even to the possibility of the working of social causes, I think he might have been led to inquire more closely into the distribution and exact character of the practice in question. He might have been led to see that we have here a problem for exact inquiry. Such a custom among ourselves must certainly own a cause different from that to which I have ascribed the Melanesian practice, but is it certain that there is no social practice among ourselves which would lead to the classing of the wife’s sister with the sister and the sister’s husband of a woman with the brother? I will only point to the practice of marrying the deceased wife’s sister, and content myself with the remark that I should be surprised if there were any general tendency to class these relatives together by a people among whom this form of marriage is the orthodox and habitual custom.