[234] _Studies in Ancient History_, I, viii, 83-146. McLennan's views are somewhat modified and further developed in his _Patriarchal Theory_, notably in chaps. xii and xiii, 181-242; and a mass of new material is presented in his _Studies_, 2d ser. (1896). [235] In his two earlier works McLennan is vague as to the exact meaning of "promiscuity" and "polyandry;" but in his letter to Darwin (1874), _Studies_, II, 50-56, he defines these terms, so that, in effect, he makes important concessions to the adherents of early monogamy and polygyny and to those critics who have questioned his theory of universal phases of progress. He says, referring to the first series of _Studies_: "The import of my reasoning is that more or less of it [promiscuity] and of _indifference_ must appear in the hordes or their sections or some of them." It is used to "denote the general conduct as to sexual matters of men without wives.... Now I agree with you that from what we know of human nature we may be sure that each man would aim at having one or more women to himself, and cases would occur wherein for a longer or shorter time the aim would be realized, and there would be instances of what we may call polygyny and monogamy--your first stage.... I take it, polygyny, monogamy, and polyandry (or its equivalents) must have occurred in every district from the first;" but the cases of polyandry would be much more numerous. "Polyandry, in my view, is an advance _from_, and _contraction_ of, promiscuity. It gives men wives. Till men have wives they may have tastes, but they have no obligations in matters of sex. You may be sure polygyny in the early stage never had the sanction of _group opinion_." This late explanation does not, however, relieve the author from responsibility for the misleading statements or obscurities of his earlier works. _Cf._ the rather too appreciative review of the second series of _Studies_ by PROFESSOR GIDDINGS, in _Annals of the Am. Academy_, IV, 97-100. [236] _Studies_, I, 83, 88-90. [237] _Ibid._, chap. viii. [238] On the three systems of kinship see POST, _Familienrecht_, 6 ff.