THE SKULL AS A BASIS FOR RACE CLASSIFICATION, Fe 
or 
Palato-alveolar breadth x 100 
Palato-alveolar length = Palato-alveolar Index, 
Dolichouranic (long vault), below 110. 
Mesuranic (medium vault), 110 to 115, 
Brachyuranic (short vault), above 115. 
As a rule, breadth exceeds length, but in Apes length 
exceeds breadth. Australian Aboriginals approximate to 
the Apes. 
Having examined the Cranium and the Face separately, 
we may now combine the two and study the relation of Face 
to Cranium. In this connection terms are used to indicate 
the relative projection of the face in front of the cranium. 
Thus the Horse, Tiger, Ape, ete., are prognathic, because the 
amount of projection is great, Among Europeans the pro- 
jection is slight, ic, orthognathic. The lower races are 
prognathic. 
Prognathism is contributed to by the projection of the soft 
parts—eg., the lips—also by the incisor teeth, and even by 
the lower jaw. This condition may also be affected by the 
amount of curvature of the skull and by the attitude of the 
skull upon the spinal column, 
In the natural attitude of the human skull the axis of 
vision is horizontal. When the skull alone is present there 
are several ways of determining the horizontal axis of vision, 
but that in common use is to place the skull with the upper 
margins of the zygomatic arches horizontal. 
To determine the amount of projection, a point is selected 
on the base, viz., the Basion. From this point the distance 
is measured, first, to the most projecting point of the upper 
jaw, viz., the alveolar point; and second, to the nasion or 
glabella. In this way 
Basi-alveolar diameter x 100 pli 
: : ~ — = Gnathie Index. 
Basi-nasal diameter 
Orthognathous, below 98—e.g., Europeans, Scotch, Bush- 
men. 
