Such, sketched in hasty outline, is the symmetrical structure which the author of the _Ancient Society_ has erected. But it has not been able wholly to withstand the shock of adverse criticism. The argument rests on too narrow a basis of investigation, and it is sometimes contradictory in its details. Its real foundation is the assumption that the nomenclatures of the classificatory systems of relationship must necessarily denote actual relationships. The truth of this assumption, however, is not self-evident. Other explanations of their meaning, some of them simpler and far more probable, have been offered. In the first place, it is evident that Morgan was misled by Fison's account of the Kamilaroi class-marriages.[204] Only in Australia was he able to find in existence, as he believed, a social organization upon the basis of sex. Yet it is by no means established that communal or even group-marriage has ever prevailed among the Australian aborigines. The criticism of Mr. Curr has raised doubt as to the trustworthiness of Fison's theory, although it may not have entirely shattered it.[205] According to Curr, the class-system is an ingenious arrangement to prevent close intermarriages. Even first cousins may not marry.[206] The Australian is very jealous of his wife, who may be betrothed to him in childhood. Wife-lending occurs, but it is not sanctioned by custom. The use of a single word for different relationships, as for father and father's brother, is not an evidence of former group-marriage, but of "poverty of language."[207] Nevertheless the Australian nomenclature is richer in terms of relationship than has been assumed by Mr. Fison. "There is hardly an Australian vocabulary in print" in which distinct translation of terms for "uncle, aunt, nephew, niece, sister-in-law, and son-in-law" do not occur.[208] [204] Published by MORGAN in _Proceedings of the Am. Academy of Arts and Science_, for 1872; and subsequently presented in full by FISON in _Kamilaroi and Kurnai_, 50 ff., 99 ff., 159 ff., _passim_; MORGAN, _Ancient Society_, 49-61. Compare MCLENNAN'S account of Australian kinship in _Studies_, II, 278-310, especially 304 ff. [205] CURR, _The Australian Race_, I, 106-42. _Cf._ also KEANE, _Man: Past and Present_, 154, 155; and CRAWLEY, _Mystic Rose_, 348, 476 ff. [206] CURR, _op. cit._, I, 111, 112. [207] _Ibid._, 116. [208] _Ibid._, 140. Compare the criticism of WESTERMARCK, _Human Marriage_, 56, 57. Mucke, as we have already seen, explains the classificatory system as being a survival of the primitive "space-relationships" of the primitive horde.[209] By Kautsky also its origin is traced to the horde in which "hetairistic monogamy" prevailed, and in which blood-relationship with the parents was not regarded. The classes, therefore, have nothing to do with descent, but each embraces all the individuals of a single generation under a common name.[210]