The most conspicuous characteristic of the Seri tribe as a whole is isolation. The geographic position and physical features of their habitat favor, and indeed measurably compel, isolation: their little principality is protected on one side by stormy seas and on the other by still more forbidding deserts; their home is too hard and poor to tempt conquest, and their possessions too meager to invite spoliation; hence, under customary conditions, they never see neighbors save in chance encounters on their frontier or in their own predatory forays—and in either case the encounters are commonly inimical. The natural isolation of the habitat is reflected in modes of life and habits of thought; and during the ages the physical isolation has come to be reflected in a bitter and implacable hereditary enmity toward aliens—an enmity apparently forming the strongest motive in their life and thought, and indeed grown into a persistent instinct. Thus the Seri stand alone in every respect; they are isolated in habitat and still more intensely isolated in habits of thought and life from all contemporaries; they far out-Ishmael the Ishmael of old on Araby’s deserts. The isolation of the Seri in thought and feeling is well illustrated by the relations with their nearest neighbors (activitally as well as geographically), the Papago Indians. The Papago are much esteemed in Sonora as fearless fighters, always ready to join or even to lead a forlorn hope; yet when the expedition of 1895 was projected it was found no easy matter to induce the picked Papago guards quartered at Costa Rica to enter Seriland. They were ready, indeed mildly eager, for fray, provided it were on the frontier; but they held back in dread from actual invasion of the territory of the hereditary enemy. Like representatives of the faith-dominated culture-grades generally, they spoke weightily of inherent rights descended from the ancient time, even back unto the creation; they repeatedly declared the right of the Seri to protect their territory because it was _theirs_; yet their converse but served to show the depth and persistence of their abhorrence of the Seri and of everything pertaining to them. And when gales arose to delay the work, when the frail craft of the party was storm-buffeted and lost for days, when they were seized with the strange sickness of the sea, when the salt and sugar mysteriously disappeared (having been secretly sacrificed to diminish suffering from thirst), when all of the earth-powers and air-powers seemed to be arrayed against the expedition, they stoically held it to be but just punishment for a sacrilegious infraction of the ancient law—and their steady adherence to duty, despite tradition and physical difficulty and constant danger, revealed a real heroism. The strain was no slight one; it may have been felt more by the stay-at-homes than by the men in action; certainly a sister of one of the party (Anton Castillo) and