The fundamental feature in the organisation of the Central Australian, as in that of other Australian tribes, is the division of the tribe into two exogamous inter-marrying groups. These two divisions may become further broken up, but even when more than two are now present we can still recognise their former existence.

In consequence of, and intimately associated with, this division of the tribe, there has been developed a series of terms of relationship indicating the relative status of the various members of the tribe, and, of necessity, as the division becomes more complex so do the terms of relationship.

In the tribes with which we are dealing we can recognise at least two important types which illustrate different grades in the development of the social organisation. The first of these is found in the Urabunna tribe, the second in the Arunta, Ilpirra, Kaitish, Waagai, Warramunga, Iliaura, and Bingongina tribes.

The less complex the organisation of the tribe the more clearly do we see evidence of what Messrs. Howitt and Fison have called, in regard to Australian tribes, “group marriage.” Under certain modifications this still exists as an actual custom, regulated by fixed and well-recognised rules, amongst various Australian tribes, whilst in others the terms of relationship indicate, without doubt, its former existence. As is well known, Mr. McLennan held that the terms must have been invented by the natives using them merely for the purpose of addressing each other or as modes of salutation.