| Summary: | Fourteen measurements taken on 260 skulls are described and analysed using variance, covariance, reduced major axes, and discriminant functions. No sexual variation is found. Changes in relative growth with age are demonstrated and discussed. Skulls from the Atlantic adult population are shown to be significantly larger than those from the Pacific in most dimensions. An important exception, nasal breadth, is significantly smaller. Differences in the regression coefficients between the Atlantic and Pacific populations are probably not significant, but some differences in position of the regression lines are highly significant. The results are compared with those of some previous authors and the boundaries between the populations considered. The recognition of E. b. nauticus for the Pacific population is justified.
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