The mastoid processes are mainly of importance as sexual
characteristics. Their value in this respect, however, differs
considerably from racial group to group, and even within a single stem
of people, such as the Indians. On the whole, however, it may be said
that in the Indian female the mastoid is somewhat more developed than
it is in the average white woman. Occasionally it is considerably more
developed, reaching the subaverage or even the average dimensions
of that of the males in the same tribe. The grade of development of
the process is of course related to the strength and activity of the
sternocleido-mastoid muscle, to which it gives attachment. Among the
Munsee the size of the mastoids on the whole is only moderate; yet
even in this series they rise in one of the female skulls to male-like
proportions.