Abstract: The Hong Kong skulls of known sex were collected by Dr. N. G. Jablonski and her colleagues in the Department of Anatomy of the University of Hong Kong. With her kind invitation, the present author measured and observed a part of this collection. The measurements of 117 craniometric traits provide the basis for a study of sexual differences and sexual assessment and for a study of their differences from the Taiyuan skulls and assessment of regional population.
T tests reveal that male Hong Kong skulls have greater linear dimensions than female ones, while the naso-malar angle and the profile angle of frontal bone in female group are statistically significantly ot very significantly greater than in male. The stepwise discriminant analysis selects basi-bregmatic height, nasal height, internal biorbital breadth, profile angle of frontal bone and depth of mandibular notch on left side as its variables in the function, and produces the accuracy of 93.1%. Using other combinations of variables, the other 5 discriminant functions are also effective.
In the comparison of regional populations, Hong Kong male skulls have longer, higher and somewhat broader cranial part, broader nose and prominent alveolar prognathism, while Taiyuan male skulls have higher facial part, that is, morphological and upper facial height, orbital height, nasal height, height of mandibular symphysis, and are combined with more prominent mental protuberance.
In general, the differences between Hong Kong male skulls and Taiyuan ones are smaller than the sexual differences in either region, so that the discriminant functions for distinguishing between these two regional populations lead to lower percentages of cases correctly classified. While the accuracy for identification of mandibles alone is as low as ca. 70%, the prediction for skulls either with or without mandibles is practicable. The discriminant function covering basi-bregmatic height, n-pr upper facial height, orbital height on left side, nasal breadth, bregmatic angle, bicoronoid breadth, arc of symphysis; mandibular angle on left side produces the accuracy of prediction of as high as 85.3% and the accuracy of blind test of 82.6%. The percentages of correct prediction for the other 3 functions are also greater than 80%. In view of the respective homogeneity of the Southern Chinese skulls and the Northern ones, these functions might be applicable to distinguish regional populations in a broader geographical range without considerable decrease of the accuracy.

Key words: Hong Kong skulls; Sexual difference; Regional population; Discriminant analysis