Note 4 — Chapter III · LIVING RACES

The usual nomenclature for cephalic index is on the basis of round numbers: broad or round headed or brachycephalic above 80; medium headed or mesocephalic between 75 and 80; narrow or long headed or dolichocephalic below 75. Yet, as the average for mankind is in the neighborhood of 79, this terminology makes far more brachycephalic than dolichocephalic peoples. Groups frequently spoken of as long headed are often really mesocephalic by the accepted definition: a large proportion of Europeans, for instance. It would result in both more accuracy and a better balancing of the limits if the three types of head form were set, as has been suggested, at 81 and 77 in place of 80 and 75.—The index of the skull (strictly, the cranial index) is two units less than that taken on the living head.