called absurd, since they are known to occur in other parts of the world. Following Riggs, Professor Kroeber does not specify which kinds of grandfather and father-in-law are classed together in Dakotan nomenclature, but in the full list given by Morgan, it is evident that one term is used for the fathers of both father and mother and for the fathers of both husband and wife. The classing of the father's father with the wife's father would be a natural result of marriage with the father's sister, while the common nomenclature for father's father and husband's father would result from marriage with the brother's daughter. It is not without significance that the features of nomenclature which would be the result of one or other, or of both these marriages, occur in a system which also bears evidence of the cross-cousin marriage, for these three forms of marriage occur in conjunction in one part of Melanesia, viz., the Torres Islands.
The foregoing instance, together with many others scattered through these lectures, will have pointed clearly to another lesson. In the present state of our knowledge a working scheme or hypothesis has largely to be judged by its utility. A way of regarding social phenomena which obstructs inquiry and leads people to overlook facts has its disadvantages, to say the least, while a scheme or hypothesis which leads people to worry out and discover things which do not lie on the surface will establish a strong claim on our consideration, even if it should ultimately turn out
