Before revision: In such cases, the community usually has unilineal descent , either patri- or matrilineal , so that any individual belongs to one of the two moiety groups by birth, and all marriages take place between members of opposite moieties.
After revision: In such cases( the community usually has unilineal descent ) either patri- or matrilineal , so that any individual belongs to one of the two moiety groups by birth, and all marriages take place between members of opposite moieties.