_The Descriptive Principle._ When we approach our subject in a purely empirical way, we are confronted with the fact that features do not, as a rule, occur sporadically but are distributed over continuous areas. Imperfect as is our knowledge of African systems, for example, we know that the descriptive feature of the Masai nomenclature does not appear everywhere, but flourishes especially among East African tribes, such as the Shilluk, Dinka, and other Upper Nile populations, and perhaps more widely where Arabic influence extends, the Arabian terminology being of a markedly descriptive character. In East Africa, indeed, there is almost quantitative proof of the dependence of kinship terminology on historical connection and geographical proximity. Among the Baganda, as among most Bantu Negroes, the descriptive feature is lacking and such a relative as the mother’s brother’s son, instead of being designated by a compound expression, is classed with the brother.[4] The Masai, who live surrounded by Bantu tribes, have a purely descriptive system for non-vocative usage but their vocative forms are in part classificatory, while some neighboring Bantu peoples have a correspondingly mixed system. The Shilluk and Dinka seem to use the descriptive principle exclusively, as do the Arabs. The Masai are undoubtedly closely allied with the Nilotes and markedly different from the Bantu. The conclusion is, therefore, inevitable that their terminology--whatever may be its ultimate _raison d’être_--is a function of their historical relations. They have descriptive features because they belong to a group of peoples of whom such features are characteristic. They have classificatory features because they have come into contact with peoples whose systems were characterized by such features and from whom they have borrowed them. The Shilluk lack the classificatory principle because they have not had the same alien influences as the Masai. The restriction of descriptive features to a definite part of Africa and their amalgamation with other features in the marginal section of this area show that kinship nomenclatures follow precisely the same rules as other elements of culture and that their distribution indicates probable or corroborates known tribal relations. The descriptive principle is not restricted to East Africa and the Semitic family, but has been found in the Persian, Armenian, Celtic, Esthonian, and Scandinavian languages.[5] Although guesses might be offered, I do not feel that our present knowledge permits definite statements as to the historical relations suggested by the total range of the descriptive principle on the face of the globe.