The fact that these naming systems are strikingly different from each other is a reminder that there was considerable cultural diversity among the original inhabitants of the Western Hemisphere. I n order to comprehend the Omaha, Crow, and Iroquois naming systems, it is important to first understand a common distinction made between types of cousins in societies following unilineal descent. For people whose culture uses the bilateral descent principle , such as most of contemporary Europe and the Americas, these cousin differences seem to be irrelevant and unnecessary. However, they are logical and easy to understand when viewed in their cultural context.
Parallel cousins are ego's father's brother's children and mother's sister's children.
In contrast, cross cousins are ego's father's sister's children and mother's brother's children. In other words, there is a crossing of gender in the parent generation with cross cousins but not with parallel ones. 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.