Various attempts have been made to account for the prevalence among peoples of all degrees of culture of what has been called “marriage by capture,” or of rites which furnish evidence of its former existence. Mr. M’Lennan traces it to infanticide, which by “rendering women scarce, led at once to polyandry within the tribe, and the capturing of women from without.” On the other hand, Sir John Lubbock ascribes the origin of “marriage by capture” to a desire on the part of individuals to acquire women for themselves, “without infringing on the general rights of the tribe.” According to this view, communal marriage was replaced by special connections, accompanied by the introduction of a foreign element, giving rise to the practice of _exogamy_. The reference to this practice (the necessity for which must, if Mr. M’Lennan’s idea is correct, have preceded “marriage by capture,” instead of the latter originating it) unnecessarily complicates the question under discussion. Although exogamy is often associated with forcible marriage, the two things are perfectly distinct, and they have had totally different origins. Mr. Morgan very justly connects the former with certain ideas entertained by primitive peoples with regard to blood relationship, and it can be explained most simply and rationally as _marriage out of the clan_, it having sprang from the belief that all the members of a clan are related by blood, and therefore incapable of being united in marriage. This view is confirmed by the fact that tribes which are _endogamous_ in relation to other tribes are _exogamous_ in the sense that they comprise several clans, the members of none of which can intermarry among themselves. We have a curious example of this limited exogamy in the Chinese, among whom persons bearing the same family name are not permitted to intermarry. True endogamy would seem to exist among very few peoples, and when it is practised the custom is probably due to special circumstances, which, giving prominence to a particular clan, have enabled them to claim a caste privilege, or it may be owing to a necessity arising from the complete severance of the members of a clan from their fellows. The scarcity of women, whether occasioned by infanticide or polygamy, may have rendered exogamy more requisite, and it may have been complicated by forcible marriage, but none of these have any real bearing on its origin.