The next step in the process of demonstrating the social significance of the classificatory system of relationship will take us to the island of Pentecost in the northern New Hebrides. When I recorded the system of this island, I found it to have so bizarre and complex a character that I could hardly believe at first it could be other than the result of a ludicrous misunderstanding between myself and my seemingly intelligent and trustworthy informants. Nevertheless, the records obtained from two independent witnesses, and based on separate pedigrees, agreed so closely even in the details which seemed most improbable that I felt confident that the whole construction could not be so mad as it seemed. This confidence was strengthened by finding that some of its features were of the same order of peculiarity as others which I had already found in a set of Fijian systems I have yet to consider. There were certain features which brought relatives separated by two generations into one category; the mother’s mother, for instance, received the same designation as the elder sister; the wife’s mother the same as the daughter; the wife’s brother the same as the daughter’s son. The only conclusion I was then able to formulate was that these features were the result of some social institution resembling the matrimonial classes of Australia, which would have the effect of putting persons of alternate generations into one social category. This idea was supported by the system of relationship of the Dieri of Australia which possesses at least one feature similar to those of Pentecost, a fact I happened to remember at the time because Mr. N. W. Thomas[13] had used it as the basis of a _reductio ad absurdum_ argument to show that terms of relationship do not express kinship. The interest of the Pentecost system seemed at first to lie in the possibility thus opened of bringing Melanesian into relation with Australian sociology, a hope which was the more promising in that the people of Pentecost and the Dieri resemble one another in the general character of their social organisation, each being organised on the dual basis with matrilineal descent. When in Pentecost, however, I was unable to get further than this, and the details of the system remained wholly inexplicable. [13] _Kinship Organisations and Group Marriage in Australia_, Cambridge, 1906, p. 123.