Phenomena that persist in isolation from their original context are technically known as ‘survivals’, and form one of the most interesting chapters of ethnology. One or two additional examples will render their nature still clearer. The boats of the Vikings were equipped for rowing as well as for sailing. Why the superfluous appliances for rowing, which were later dropped? As soon as we learn that the Norse boats were originally rowboats and that sails were a later addition, the rowing equipment is placed in its proper cultural setting and the problem is solved. Another example may be offered from a different phase of life. Among the Arapaho Indians there is a series of dance organizations graded by age. Membership is acquired by age-mates at the same time, each receiving the requisite ceremonial instructions from some older man who passed through the dance in his day. These older men, who are paid for their services by the candidates, may belong to any and all of the higher organizations. Oddly enough, each group of dancers is assisted by a number of ‘elder brothers’, all of whom rank them by _two_ grades in the series of dancers. This feature is not at all clear from the Arapaho data alone. When, however, we turn to the Hidatsa Indians, with whom there is evidence this system of age-societies originated, we find that here the youngest group of men does not buy instructions from a miscellaneous assemblage of older men, but buys the dance outright from the whole of the second grade; this group, in order to have the privilege of performing a dance, must buy that of the third grade, and so on. In all these purchases the selling group seeks to extort the highest possible price while the buyers try to get off as cheaply as possible and are aided by the second higher group, _i.e._, the group just ranking the sellers. Here the sophomore-senior versus freshman-junior relationship is perfectly intelligible; both the freshman and the junior, to pursue the analogy, bear a natural economic hostility against the sophomore, and vice versa. The Arapaho usage is intelligible as a survival from this earlier Hidatsa condition.