INDEX, CEPHALIC, CRANIAL. PELVIC, cte. A term employed by anthropologists to mark the proportions of certain related parts of the lunnan body. especially of the head or cranium, in order to distinguish biological varieties in mankind. The most important of these, and the easiest to obtain, is the ratio of the width of the head to the length, called cranial index for the skull. and cephalie index for the living subject. To avoid the decimal point at the beginning of the index, the width of the skull is multiplied by 100 and divided by the length, the formula being W100 – — = I. The extreme length is between the glabella and the most prominent portion of the occiput. and the width is the greatest breadth, wherever that may be. All applianees necessary for these measurements are a set of calipers and a rule, in centimeters or in inches.
Three terms are applied by anthropologists to beads, according to these measures. Those having cephalic indexes with a ratio below 80 are called dolichocephalic, those between 80 and S2 are mesocephalic, and those above S2 are brachy cephalic. For crania, or skulls of the dead, the indexes are about twu points lower. In the nu merous cases where a finer subdivision is neces sary, a quinary method of nomenclature is fol lowed, the Germans adopting a series called the Frankfort Agreement, the French. the scheme of Broca, modified by Deniker, as follows: Dolichocephalic skulls of exceptional length have reached an index of 58. the lowest limit, while braehycephalic examples have gone as high as 90 or even 100.
Before proceeding to other indexes it should be stated that the cranial and cephalic indexes just described are far from being a perfect guide to the classification of mankind, for the subdi visions of the human species have no governing rule and are not subspecies. but separate varieties and mixtures, as with domestic animals.
Again, the ratio between the width and the length of the skull does not give complete infor mation as to its shape. The measurements, there fore, lead to uncertain conclusions, since precisely the same figures would be obtained from crania or heads of widely different cross-section, so that one having an almost rectangular shape, an oval with a narrow end far in front, and a long ellipse would lead to the same index. Unless a large number of skulls among the same people are meas ured and give something like a uniform result, the measurements are an unsafe guide. Very little good arises from simply adding a number of indexes and dividing by a number of observa tions. The average result might be a number to which not a single bead in the whole series meas ured would correspond. It is customary, there
fore, to tabulate results by co6rdinates. Fre quently. when such a plan is pursued there arise several apexes. as in Italy, the higher number representing the brachycephalic Northern Italians with Celtic blood in their veins, and the lower number the Southern long-headed Mediterranean `type.
The cranial and cephalic indexes are not pre cisely eoiirdinated with purely descriptive char acteristics of the human body. It cannot be said that any one of the subspecies of man is either dolichocephalie or brachycephalic, but tendencies toward one or the other exist, as the following table of cephalic indexes shows: Caroline Islanders (black) 69 4 Kashmirians (yellow-white). Bakongo (black) . 72.5 Ilindus (white, mixed) 72 S Karaya Indians, South America (red) ......... 73.0 Australians (straight-haired blacks) 74 Norwegians (blondes) Corsicans (white) . • 76 6 Spaniards of Valencia 76 British Isles 77-79 Parsis of Bombay (white) Koreans (yellow) Malays (brown) 8". 8 Negritos, Philippines (black) . 84.7 Arawaks, Guiana .S2.6 Saras, Chad-basin, Sudan (black) 82.4 Samoans (brown mixed) Votyake (yellow) .S2 .1.1 Walloons (white) . 82.2 Italians (white) . 132 . 7 Armenians (white) l'iedmontese (white) . 65 . 9 Sudanese (brown). .66.3 Savoyards (white) .86.9 Tahitians (brown) S.5 . 6 Aleuts (red) S7.8 Magyars (mixed) 87.8 Burmese (yellow) S5.7 Aissor Transcaucasian (white-yellow) Among the European whites the people of the British Isles are mesocephalic; of France the index is 7S-SS; of Italy, 75-87; of Spain, 77-SO; Switzerland, 76-85, with two types, the long and the short head; Austria, S0-S4.
Other indexes than those expressing the relation of width to length are also employed. The facial index is the ratio of the width to the height. from the glahella to the alveolar border, and separates skulls into brachyfacial and doliehofacial. The ratio of width to length in the orbital orifice sep arates crania into megasemes (90 and upward), meso.sernes (S9 to S4), and micrnsemes (below 84). The nasal index is the ratio between the width of the bony mass of the nose and its height. giving rise to leptorhine, or narrow-nosed. platy Thine, or flat-nosed, with the intermediate term. mesorhine. The dental index is based upon the importance which naturalists place on dentition in the classification of mammals. Upon the ratio of the size of the teeth to related parts, Flower divides men into megadont, mesodont, and micro dont ; and this series bears a surprising relation to the three anthropometrie types of man—Ne groid, Mongoloid. Caucasoid.