Note 59 — Chapter II

Skulls may also be grouped by sections (for instance, ascending to the quinary nomenclature of the cephalic index) to see what is the proportional part of each of these sections. Thus if we take a series of 10 skulls having the following indices, 75, 77, 78, 80, 80, 81, 81, 81, 82, 84, their average index will be expressed by the figure 80 (the sum of the indices divided by the number of skulls), while the most frequent mean index will be 81. Further, the series should be considered as not very homogeneous, for it comprises 1 dolichocephalic, 1 sub-dolichocephalic, 1 mesocephalic, 6 sub-brachycephalic, and 1 brachycephalic.