near Port Darwin in the north, in which descent is thus counted.

In all that vast extent of country the development of the social organisation has been from four sub-classes to eight, and on the basis of male descent. It is therefore not surprising that so far no tribes have been met with with the eight sub-classes and descent still maintained in the female line.

Messrs. Spencer and Gillen point out that each sub-class in the Arunta tribe is in fact further divided into two groups, with the effect that, while for example a Panunga man marries one of the Purula women, those women are divided into two groups, the members of one of which stand in the relationship of "Unawa," whom he may marry, while the members of the other stand in the relationship of "Unkulla," whom he may not marry.^[1]

The other two sub-classes are similarly divided, so that the complete eight sub-class system is shown in the diagram below^[2]:—

Panunga		Panunga		Purula		Purula
		Uknaria		Ungalla
Bulthara		Bulthara		Kumara		Kumara
		Appungarta		Umbitchana

The fact that the old name is still used for one-half of a sub-class, while a new one has been given to the other half, is very significant of the manner in which the segmentation of the class divisions has been made by deliberate intention.

The eight sub-class system prevails in a large number of tribes extending from the Urabunna a little north of Lake Eyre to near Port Darwin, in all of which descent is counted in the male line.

1. ↑ Op. cit. pp. 71, 72.
2. ↑ Op. cit. p. 72.