A man of clan A and totem group _l_ may marry only a woman of clan B and totem group _p_; the children, however, do not belong to the totem _p_, but to another specifically defined totem group, _q_, of clan B. The way in which these various forms of exogamy affect the marriage relations of the children that are born from such unions is fairly obvious. Turning first to form I--unlimited exogamy--it is clear that, in the case of maternal descent, which here appears to be the rule, none of the children of the mother may marry except into the clan of the father; in paternal descent, conversely, they may marry only into the clan of the mother. Marriage between brothers and sisters, thus, is made impossible. Nor may a son marry his mother where maternal descent prevails, or a daughter her father in the case of paternal descent. In the former case, however, the marriage of father and daughter would be permitted, as would that of mother and son in the latter. The marriage of a son or daughter with relatives of the mother who belong to the same clan is not allowed in the case of maternal descent. The son, for example, may not marry a sister of his mother, nor the daughter a brother of the mother, etc. Since it is maternal descent that is dominant in the case of unlimited exogamy, the most important result of the latter is doubtless its prevention of the marriage of brother and sister, in addition to that of a son with his mother. The system of paternal descent, of course, involves a corresponding change in marriage restrictions.