m kin, phratry, class, or other form of association, is a fraction
of a tribe; and before we proceed to deal with kinship organisations, it
will be necessary to say a few words on the nature of the tribe and the
family. In Australia the tribe is a local aggregate, composed of
friendly groups speaking the same language and owning corporately or
individually the land to which the tribe lays claim. A change of tribe
is effected by marriage plus removal, and possibly by simple residence;
children belong to the tribe among which their parents reside. In the
ordinary tribe each member seems to apply to every other member one or
other of the kinship terms; and this no doubt accounts for the feeling
of tribal solidarity already mentioned. There are however certain tribes
in which the marriage regulations, as with the Urabunna, so split the
intermarrying fractions, that the tribe is, as it were, divided into
water-tight compartments; how far kinship terms are applied under these
circumstances our information does not say.

The tribe is defined by American anthropologists as a union of hordes or
clans for common defence under a chief. The American tribe differs in
two respects, at least, from the Australian tribe; in the first place,
marriage outside the tribe is exceptional in America and common in
Australia; in the second place, the stranger gains entrance to the
American tribe only by adoption; and we may probably add, thirdly, that
the American tribe does not invariably lay claim to landed property or
hunting rights.

The tribe is subdivided in various ways. In addition to the various
forms of natal and other associations, there is, at any rate in
Australia, a local organisation; the local group is often the owner of a
portion of the tribal area. This local group again falls into a number
of families (in the European sense), and the land is parcelled out among
them in some cases, in others it may be the property of individuals. But
there is a great lack of clearness with regard to the bodies or persons
in whom landed property is vested. The composition of the local group
varies according to the customs of residence after marriage, and the
rules by which membership of the kinship organisation is determined.
These two forces acting together may produce two types of local group:
(1) the mixed group, in which persons of various kinship organisations
are scattered at random; (2) the kin group, in which either all the
males or all