Cranial non-metric variation in north and central Mexico.

Fifty cranial non-metric traits were scored on twenty series of crania from north and central Mexico in the American Museum of Natural History. Additional crania from three of the series were scored in the Musco Nacional de Antropología. Mexico City. Although a total of 471 crania and 316 mandibles were registered, only 11 series containing 387 crania and 270 mandibles, were of sufficient length for statistical analysis. Trait frequencies in these series were compared by multidimensional scaling and principal component analysis. The results suggest a degree of biological continuity in the Basin of Mexico over a twenty-five hundred year period, although the later samples from that area exhibit signs of some gene flow from more northern populations.