GROUP MARRIAGE.--A remarkable system of relationships, with which is combined a series of regulations framed with the object of pointing out what persons are entitled to enter into the marital relation, is found to be prevalent in nearly all uncivilized peoples. The members of a tribe are divided into two or more groups, each of which consists of persons who are nearly related by blood, and who are forbidden, therefore, to intermarry. One of the tribes of Central Australia, the Dieyerie, has a legend which explains the marriage system common to them and to all the other tribes, as being intended to prevent the evil effects of intermarriage between persons very near of kin. The story is valuable as showing the opinion entertained by savages as to the effect on the race of breeding in and in--a subject to which we may have occasion to make further reference. Dr. J. F. McLennan and other writers on primitive marriage refer to the practice among certain _civilized_ peoples of antiquity of what we regard as incestuous marriage, in support of the view that in the early history of mankind intercourse between the sexes was promiscuous.[21:A] Such an explanation is entirely uncalled for, however, as the custom was intended to secure purity of blood, that is, blood of a particular line of ancestors. Such marriages were known only to a few peoples, and they were evidently of comparatively late origin. Whether the purity of blood was attended with improvement of the stock may be doubted; as, whatever may have been the actual origin of the marriage regulations of the numerous peoples among whom the classificatory system of relationship is established, they are intended, without question, to prevent the intermarriage of persons who are regarded as near blood relations, the general disapproval of which must have had some sufficient reason, or, at all events, must have originated in ideas supposed to furnish good grounds for it.