The gender of the cousin is not relevant in making this distinction. T he importance of this categorization of cousins can be understood in terms of descent relationships. Note that in the red patrilineage shown below, parallel cousins are members of ego's unilineage , while cross cousins are not. 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.