Inquiries that have been made among the natives of Samoa, Futuna, Rotuma, Uea, and Malanta (Solomon Group), have satisfied me that the practice of concubitant marriage is unknown in those islands; indeed, in Samoa and Rotuma, not only is the marriage of cousins-german forbidden, but the descendants of a brother and sister respectively, who in Fiji would be expected to marry, are there regarded as being within the forbidden degrees as long as their common origin can be remembered. This rule is also recognized throughout the Gilbert Islands, with the exception of Apemama and Makin, and is there only violated by the high chiefs. In Tonga, it is true, a trace of the custom can be detected. The union of the grandchildren (and occasionally even of the children) of a brother and sister is there regarded as a fit and proper custom for the superior chiefs, but not for the common people. In Tonga, other things being equal, a sister's children rank above a brother's, and therefore the concubitant rights were vested in the sister's grandchild, more especially if a female. Her parents might send for her male cousin to be her _takaifala_ (_lit._, "bedmaker") or consort. The practice was never, however, sufficiently general to be called a national custom. So startling a variation from the practice of the other Polynesian races may be accounted for by the suggestion that the chiefs, more autocratic in Tonga than elsewhere, having founded their authority upon the fiction of their descent from the gods, were driven to keep it by intermarriage among themselves, lest in contaminating their blood by alliance with their subjects their divine rights should be impaired. A similar infringement of forbidden degrees by chiefs has been noted in Hawaii, where the chief of Mau'i was, for reasons of state, required to marry his half-sister. It is matter of common knowledge that for the same reason the Incas of Peru married their full-sister, and that the kings of Siam marry their half-sisters at the present day. _Origin of the custom._--I venture to offer here three possible explanations of the origin of this custom, leaving it to the acknowledged authorities upon the history of marriage to point out what in their opinion is the true explanation:--