In any case, however, there is a test of social advance. There is an
acknowledged advance when a tribe is divided into, not two, but four or
eight divisions, which may not intermarry.[IBID. p. 454] The Euahlayi have
four such divisions. In each of their intermarrying phratries are two
'Matrimonial Classes,' each with its name, and these are so constituted
that a member of the elder generation can never marry a member of the
succeeding generation. This rule prevents, of course, marriage between
parent and child, but such marriages never do occur in the pristine
tribes of the Darling river which have no such classes. The four-class
arrangement excludes from intermarriage all persons, whether parents
and children or not, who bear the same class name, say Hippai.

Among the central and northern tribes, from the Arunta of the
Macdonnell hills to the Gulf of Carpentaria, the eight-class rule
exists, and it is, confessedly, the most advanced of all.

In this respect, then, the Arunta of the centre of Australia are
certainly more advanced than the Euahlayi. The Arunta have eight, not
four, intermarrying classes. In the matter of rites and ceremonies,
too, they are, in the opinion of Messrs. Spencer and Gillen, more
advanced than, say, the Euahlayi. They practise universal 'subincision'
of the males, and circumcision, in place of the more primitive knocking
out of the front teeth. Their ceremonies are very prolonged: in Messrs.
Spencer and Gillen's experience, rites lasted for four months during a
great tribal gathering. That the Arunta could provide supplies for so
prolonged and large an assembly, argues high organisation, or a region
well found in natural edible objects. Yet the region is arid and barren,
so the organisation is very high. For all these reasons, even if we do not
regard paternal descent of the totem as a step in progress from maternal
descent, the Arunta seem greatly advanced in social conditions.