The first thing which strikes us as soon as we begin studying primitive folk is the complexity of the organization of marriage relations under which they are living. With most of them the family, in the sense we attribute to it, is hardly found in its germs. But they are by no means loose aggregations of men and women coming in a disorderly manner together in conformity with their momentary caprices. All of them are under a certain organization, which has been described by Morgan in its general aspects as the "gentile," or clan organization.(7) To tell the matter as briefly as possible, there is little doubt that mankind has passed at its beginnings through a stage which may be described as that of "communal marriage"; that is, the whole tribe had husbands and wives in common with but little regard to consanguinity. But it is also certain that some restrictions to that free intercourse were imposed at a very early period. Inter-marriage was soon prohibited between the sons of one mother and her sisters, granddaughters, and aunts. Later on it was prohibited between the sons and daughters of the same mother, and further limitations did not fail to follow. The idea of a gens, or clan, which embodied all presumed descendants from one stock (or rather all those who gathered in one group) was evolved, and marriage within the clan was entirely prohibited. It still remained "communal," but the wife or the husband had to be taken from another clan. And when a gens became too numerous, and subdivided into several gentes, each of them was divided into classes (usually four), and marriage was permitted only between certain well-defined classes. That is the stage which we find now among the Kamilaroi-speaking Australians. As to the family, its first germs appeared amidst the clan organization. A woman who was captured in war from some other clan, and who formerly would have belonged to the whole gens, could be kept at a later period by the capturer, under certain obligations towards the tribe. She may be taken by him to a separate hut, after she had paid a certain tribute to the clan, and thus constitute within the gens a separate family, the appearance of which evidently was opening a quite new phase of civilization.