Discusses the evolution of marriage systems; considers the scheme of development CD proposes: 1. Polygyny and monogamy; 2. Polyandry; 3. Promiscuity; 4. Polygyny and monogamy in recurrence. Explains what he understands by promiscuity. JFM believes that polygyny, monogamy, and polyandry must have occurred in "every district from the first, and grown up together into systems sanctioned by usage first and then law". Considers polygyny necessarily the privilege of the few and, as a system, believes it had less to do than any other with the history of marriage. He sees polyandry as an advance from promiscuity and the stage at which contractual obligations between men and their wives begin.