These distinctions can be critical in determining who an individual may and may not marry and with whom there is likely to be mutual assistance obligations. T he Omaha kin naming system is characteristic of societies that use patrilineal descent. Relatives are lumped together on the basis of descent and gender. This reflects the comparative unimportance of the mother's side of the family in a society that strongly follows the patrilineal descent principle. A n almost mirror image of the Omaha pattern is the matrilineally based Crow kin naming system .
Relatives are also lumped together on the basis of descent and gender.
This reflects the comparative unimportance of the father's side of the family in a society that strongly follows the matrilineal principle of descent. D ifferences between the Omaha and Crow systems can be seen in the terms of reference for cross cousins and whether or not uncles and aunts are lumped with them. These differences stem from the fact that the Omaha system is patrilineal and the Crow is matrilineal. This merging is related to shared membership in unilineages, as it is in the Omaha and Crow systems. However, the Iroquois system may be either patrilineal or matrilineal and is usually not as strongly one or the other.