L 
CRANIOLOGY. 175 
Uniformity in these measurements, however, is far from complete since many anthropologists 
compare the width with the length = 100. 
The proportion of the face-width to the width of the calvaria is roughly expressed by the use of 
the terms cryptozygous and phenozygous as applied to the skull. In the former case the 
zygomatic arches are concealed, when the skull is viewed from above, by the overhanging and 
projection of the sides of the cranial box ; in the latter instance, owing to the narrowness of the 
ealvaria, the zygomatic arches are clearly visible. 
The projection of the face, so characteristic of certain races (Negroes for example), may be 
estimated on the living by measuring the angle formed by two straight lines, the one passing from 
the middle of the external auditory meatus to the lower margin of the septum of the nose; the 
other drawn from the most prominent part of the forehead above to touch the incisor teeth 
below. The angle formed by the intersection of these two lines is called the facial angle 
(Camper), and ranges from 62° to 85°. The smaller angle is characteristic of a muzzle-like 
projection of the lower part of the face. The larger angle is the concomitant of a more vertical 
rofile. The degree of projection of the upper jaw in the macerated cranium is most readily 
Heformaned by employing the gnathic or alveolar index of Flower. This expresses the relative 
proportions of the basialveolar and basinasal lengths, the latter being regarded as=100, 
thus— 
Basialveolar length x 100 
Basinasal length = Gnathic index. 
The results are conveniently grouped into three classes :— 
Orthognathous, index below 98: including mixed Europeans, ancient Egyptians, ete. 
Mesognathous, index from 98 to 103: Chinese, Japanese, Eskimo, Polynesians (mixed). 
Prognathous, index above 103: Tasmanians, Australians, Melanesians, various African 
Negroes. 
The form of the nasal aperture in the macerated skull is of much value from an ethnic 
standpoint, as it is so intimately associated with the shape of the nose in the living. The 
greatest width of the nasal aperture is compared with the nasal height (measured from the nasion 
to the lower border of the nasal aperture) and the nasal index is thus determined :— 
Nasal width x 100 
Nasal height SEES 
Skulls are— 
Leptorhine, with a nasal index below 48: as in mixed Europeans, ancient Egyptians, 
American Indians, ete. 
Mesorhine, with an index ranging from 48 to 53: as in Chinese, Japanese, Malays, ete. 
Platyrhine, with an index above 53: as in Australians, Negroes, Kaftirs, Zulus, ete. 
The form of the orbit varies considerably in different races, but is of much less value from the 
standpoint of classification. The orbital index expresses the proportion of the orbital height to 
the orbital width, and is obtained by the following formula :— 
Orbital height x 100 
Orbital width — Orhitalinds. 
The orbital height is the distance between the upper and lower margins of the orbit at the 
middle; whilst the orbital width is measured from a point where the ridge which forms the 
posterior boundary of the lachrymal groove meets the fronto-lachrymal suture (Flower), or 
from the dacryon (Broca) to the most distant point from these on the anterior edge of the outer 
border of the orbit. 
The form of the orbital aperture is referred to as— 
Megaseme, if the index be over 89 ; 
Mesoseme, if the index be between 89 and 84; 
Microseme, if the index be below 84. 
The variations met with in the form of the palate and dentary arcade may be expressed by 
the palato-maxillary index of Flower. The length is measured from the alveolar point to a 
line drawn across the hinder borders of the superior maxillary bones, whilst the width is taken 
between the outer borders of the alveolar arch immediately above the middle of the second 
molar tooth. To obtain the index, the following formula is employed :— 
Palato-maxillary width x 100 
Palato-maxillary length so RULES Tope ik IG 
For purposes of classification Turner has introduced the following terms :— 
Dolichuranic, index below 110. 
Mesuranic, index between 110 and 115. 
Brachyuranic, index above 115. 
As has been elsewhere stated (p. 178), the size of the teeth has an important influence on the 
architecture of the skull. Considered from a racial standpoint, the relative size of the teeth to 
