The course of evolution has been, not, as group-marriagers contend, from group to individual terms of relationship but from terms descriptive of status to terms descriptive of relationship.
It is, in fact, on any hypothesis, impossible to deny this. Whatever terms of relationship may have meant in the past, no believer in group marriage contends that they represent anything actually existing. But this is equivalent to admitting that they express status and not relationship, and no proof has ever been given that they were ever anything else.
 p. 163.
Theories of group marriage. Meaning of group.
Dieri customs. Tippa-malku
marriage. Obscure points. Pirrauru. Obscure points. Relation of
pirrauru to tippa-malku unions. Kurnandaburi. Wakelbura customs.
Kurnai organisation. Position of widow. Piraungaru of Urabunna.
Pirrauru and group marriage. Pirrauru not a survival. Result of
scarcity of women. Duties of Pirrauru spouses. Piraungaru:
We now come to the marriage customs of the Australian natives of the present day and the supposed survivals of group marriage. In dealing with the question of group marriage we are met with a preliminary difficulty. No one has formulated a definition of this state, and the interpretations of the term are very diverse.
Fison, for example, says group marriage does not necessarily imply actual giving in marriage or cohabitation; all it means is a marital right or rather qualification which comes by birth. He argues however on a later page that Nair polyandry, which is more properly termed promiscuity, is group marriage. Much the same view is taken by A.H. Post, who regards the theory of pure promiscuity and the undivided commune as untenable.
Kohler, on the other hand, speaks of group marriage as existing among the Omahas, a patrilineal tribe, be it remarked; but means by that no more than adelphic polygyny.
Spencer and Gillen criticise Westermarck’s use of the term “pretended group marriage” and assert it to be a fact among the Urabunna. On the very next page group marriage is spoken of as having preceded the present state of things. Both statements cannot be true.
For the purposes of the present work I understand group marriage to mean promiscuity limited by regulations based on organisations such as age-grades, phratries, totem-kins, or local groups.