If this descriptive mode of nomenclature be thus the outcome of a social organisation of which the essential element is the extended family, I need hardly point out how natural it is that we should find this kind of nomenclature so widely in Europe. The presence of this descriptive terminology in Celtic and Scandinavian languages, in Lithuanian and Esthonian, would be examples of the persistence of a form of nomenclature which had its origin in the kindred of the extended family. On this view we must believe that, in other languages of Europe, this mode of nomenclature has gradually been replaced by one dependent on the social institution of the family in the narrow sense. At this point I should like to sum up briefly the position to which our argument has taken us. I have first shown the dependence of a number of special features of the classificatory system of relationship upon special forms of marriage. Then I have shown that certain broad varieties of the classificatory system are to be referred to different forms of social organisation and to the different degrees in which the regulation of marriage by means of clan-exogamy has been replaced by a mechanism dependent upon kinship or genealogical relationship. From that I was led to refer the general features of the classificatory system to the dependence of this system upon the social unit of the clan as opposed to the family which I believe to be the basis of our own terminology of relationship. I then pointed to several features of the classificatory system which suggest that it arose in that special variety of the clan-organisation in which a community consists of two exogamous moieties, forming the social structure usually known as the dual organisation. I considered more fully the dependence of our own mode of denoting relatives upon the social institution of the family, and then a study of the descriptive terminology of relationship has led me to suggest that certain modes of denoting relationship in Egypt, the Sudan and many European countries may be examples of a third main variety of system of relationship which has arisen out of the patriarchal or extended family. We should thus have three main varieties of system of relationship in place of the two which have hitherto been recognised, having their origins respectively in the clan, in the family in the narrow sense, and in the extended or patriarchal family. These three varieties may be regarded as genera within each of which are species and varieties depending upon special social conditions which have arisen within each kind of social grouping, either as the result of changes within each form of social organisation or of transitions from one form to another. We know of a far larger number of such varieties within the classificatory system than within those due to the two forms of the family, and this is probably due in some measure to the fact that the classificatory system is still by far the most widely distributed form