women, and he was to
her the principal husband among others. This fact in no small degree
contributed to the confusion among missionaries, who regarded group
marriage now as a disorderly community of women, now as an arbitrary
adultery. Such a habitual pairing would gain ground the more the gens
developed and the more numerous the classes of "brothers" and "sisters"
became who were not permitted to marry one another. The impulse to
prevent marriage of consanguineous relatives started by the gens went
still further. Thus we find that among the Iroquois and most of the
Indians in the lower stage of barbarism marriage is prohibited between
all the relatives of their system of kinship, and this comprises several
hundred kinds. By this increasing complication of marriage restrictions,
group marriage became more and more impossible; it was displaced by the
pairing family. At this stage one man lives with one woman, but in such
a manner that polygamy, and occasional adultery, remain privileges of
men, although the former occurs rarely for economic reasons. Women,
however, are generally expected to be strictly faithful during the time
of living together, and adultery on their part is cruelly punished. But
the marriage-tie may be easily broken by either party, and the children
belong to the mother alone, as formerly.

In this ever more extending restriction of marriage between
consanguineous relations, natural selection also remains effective. As
Morgan expresses it: "Marriages between gentes that were not
consanguineous produced a more vigorous race, physically and mentally;
two progressive tribes intermarried, and the new skulls and brains
naturally expanded until they comprised the faculties of both." Thus
tribes composed of gentes necessarily either gained the supremacy over
the backward ones or, by their example, carried them along in their
wake.

The development of the family, then, is founded on the continual
contraction of the circle, originally comprising the whole tribe, within
which marital intercourse between both sexes was general. By the
continual, exclusion, first of near, then of ever remoter relatives,
including finally even those who were simply related legally, all group
marriage becomes practically impossible. At last only one couple,
temporarily and loosely united, remains; that molecule, the dissolution
of which absolutely puts an end to marriage. Even from this we may infer
how little the sexual love of