McLennan, practised in England and copied elsewhere, with
the fact that he has done more harm with his ill-conceived contrast of
exogamous and endogamous tribes than he has done good by his
investigations.

Moreover, in the course of time more and more facts became known that
did not fit into his neat frame. McLennan knew only three forms of
marriage: polygamy, polyandry and monogamy. But once attention had been
directed to this point, then more and more proofs were found that among
undeveloped nations there were connubial forms in which a group of men
possessed a group of women. Lubbock in his "Origin of Civilization"
(1870) recognized this "communal marriage" as a historical fact.

Immediately after him, in 1871, Morgan appeared with fresh and, in many
respects, conclusive material. He had convinced himself that the
peculiar system of kinship in vogue among the Iroquois was common to all
the aborigines of the United States, and practised all over the
continent, although it was in direct contradiction with all the degrees
of relation arising from the connubial system in practice there. He
prevailed on the federal government to collect information on the
systems of kinship of other nations by the help of question blanks and
tables drawn up by himself. The answers brought the following results:

1. The kinship system of the American Indians is also in vogue in Asia,
and in a somewhat modified form among numerous tribes of Africa and
Australia.

2. This system finds a complete explanation in a certain form of
communal marriage now in process of decline in Hawaii and some
Australian islands.

3. By the side of this marital form, there is in practice on the same
islands a system of kinship only explicable by a still more primeval and
now extinct form of communal marriage.

The collected data and the conclusions of Morgan were published in his
"Systems of Consanguinity and Affinity," 1871, and discussion
transferred to a far more extensive field. Taking his departure from the
system of affinity he reconstructed the corresponding forms of the
family, thereby opening a new road to scientific investigation and
extending the retrospective view into prehistoric periods of human life.
Once this view gained recognition, then the frail structure of
McLennan, would vanish into thin air.

McLennan defended his theory in the new edition of "Primitive Marriage"
(Studies in Ancient History, 1875). While he himself most artificial