I have traced the progressive development of the social organisation, from the two-class system with maternal descent through various stages, to eight sub-classes and descent counted in the male line. I now return to the two-class system, with female descent, in order to trace out the alteration of the social organisation, in another direction, with different results.

The most convenient starting-point in this line of inquiry will be the Wotjobaluk tribe, whose northern limits adjoin the southern boundary of the Wiimbaio, whose class names, Mukwara and Kilpara, are the equivalents of the Wotjobaluk classes Gamutch and Krokitch respectively. The class system of this tribe is in some respects peculiar.