I dare say, though, the missing link is somewhere in the legends.

I rather think the Central Australians have the key to it.
One old man here was quite an Ibsen with his ghastly version of heredity.
He said, when I asked him what harm it would do for, say, a Beewee totem man to come from the Gulf country, where his tribe had never had any communication with ours, and marry a girl here,--that all Beewees were originally changed from the Beewee form into human shape.

The Beewee of the Gulf, originally, like the Beewee here, had the same animal shape, and should two of this same blood mate the offspring would throw back, as they say of horses, to the original strain, and partake of iguana (Beewee) attributes either in nature or form.
From the statements just given, it will be seen that the Euahlayi are in the Kamilaroi stage of social organisation.

They reckon descent in the female line: they have 'phratries' and four matrimonial classes, with totems within the phratries.

In their system of 'multiplex-totems' or 'sub-totems' they resemble the Wotjobaluk tribe.