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
