Two writers, [21] basing their observations on color, physical resemblances, and the fact that the Tinguian blacken their teeth and tattoo their bodies, are convinced that they are the descendants of Japanese castaways; while _Moya_ [22] states that the features, dress, and customs of this people indicate their migration from the region of the Red Sea in pre-Mohammedan times. Finally, _Quatrefages_ and _Hamy_ are quoted as regarding the Tinguian as modern examples of "the Indonesian, an allophylic branch of the pure white race, non-Aryan, therefore, who went forth from India about 500 B.C." [23] _Dr. Barrows_ [24] classes all the pagan tribes of northern Luzon--the pygmies excepted--with the Igorot, a position assailed by _Worcester_, [25] particularly in regard to the Tinguian; but the latter writer is convinced that the Apayao and Tinguian are divisions of the same people, who have been separated only a comparatively short time. In the introduction to the present volume (p. 236) I have expressed the opinion that the Tinguian and Ilocano are identical, and that they form one of the waves of a series which brought the Apayao and western Kalinga to northern Luzon, a wave which reached the Islands at a later period than that represented by the Igorot, and which originated in a somewhat different region of southeastern Asia. [26] In order to come to a definite decision concerning these various theories, we shall inquire into the cultural, linguistic, and physical types of the people concerned. The most striking cultural differences between the Igorot and the Tinguian, indicated in the introduction, will be brought out in more detail in the following pages, as will also the evidence of Chinese influence in this region. Here it needs only to be restated, that there are radical differences in social organization, government, house-building, and the like, between the Igorot-Ifugao groups, and the Ilocano-Tinguian-Apayao-Kalinga divisions. All the tribes of northwestern Luzon belong to the same linguistic stock which, in turn, is closely related to the other Philippine languages. There are local differences sufficiently great to make it impossible for people to communicate when first brought together, but the vocabularies are sufficiently alike, and the morphology of the dialects is so similar that it is the task of only a short time for a person conversant with one idiom to acquire a speaking and understanding knowledge of any other in this region. It is important to note that these dialects belong to the Philippine group, and there seems to be very little evidence of Chinese influence [27] either in structure or vocabulary. [28] The various descriptions of the physical types have been of such a conflicting nature that it seems best at this point to present rather detailed descriptions of the Tinguian, Ilocano, and Apayao, and to compare these with the principal measurements of the other tribes and peoples under discussion.