The population estimates of the past are naturally vague. In 1645 Ribas spoke of the tribe as “a great people”; and a century later Villa-Señor expressed himself in somewhat similar terms, and described their range in such manner as to indicate a population running into thousands. A few years after Villa-Señor (in 1750), Parilla claimed to have annihilated the entire tribe, with the exception of 28 captives; but according to Velasco’s estimates, the people numbered fully 2,000 some thirty years later, when the tribe was, however, once more nominally annihilated. In 1824 Troncoso estimated the Seri at over 1,000, and two years later Retio reckoned the population of Isla Tiburon alone at 1,000 or 1,500, while Hardy thought the entire tribe might number 3,000 or 4,000 at the utmost. About 1841 De Mofras put the aggregate population at 1,500; and at the time of the vigorous invasion by Andrade and Espence (1844), when a considerable number of the tribe were captured and a few slain, the total population was estimated at about 550—though it is probable that a good many tribesmen were left out of the reckoning. According to the chroniclers, a number of the Seri were slain after, as well as before, this invasion; and in 1846 Velasco estimated the tribe at less than 500, including 60 or 80 warriors. This estimate was in harmony with that made by Señor Encinas, who reckoned the tribe at 500 or 600 at the beginning of his war, in which half the tribe lost their lives. The figures of Velasco and Encinas correspond fairly with the reckoning by Mashém in 1894, due allowance being made for natural increase and for the losses through occasional skirmishes; and Mashém’s count is shown not to be excessive by the considerable number of jacales and rancherias and well-trodden pathways found throughout Seriland in 1895. On the whole it seems probable that the Seri population extended well into the thousands at the time of the Caucasian invasion; it seems probable, also, that the body was then too large for stability under its feeble institutional bonds, and hence threw off by fission the Guayma and Upanguayma fractions, and the Angeles, Populo, and Pueblo Seri fragments. Furthermore, it seems probable that the prolific group fairly held its own against these normal losses and repeated decimations by battle up to the Migueletes-Cimarrones war of 1780, despite the vaunted annihilation in 1750; but that thenceforward the death-rate due to increasingly frequent encounters with incoming settlers exceeded the birth-rate, gradually reducing the tribe from some 2,000 to the 250 or 300 surviving the Encinas conflict. Finally, it seems probable that the tribe has again held its own and perhaps increased slowly under the renewed isolation of the last decade or two. SOMATIC CHARACTERS