302 Proceedings of Boy al Society of Edinburgh. [sess. 
Conjoined with this, however, the degree of frontal curvature 
should always he determined. This can he done hy dropping a 
perpendicular on the hregrna line from the point of maximum 
frontal curvature, and comparing the length of such a line with 
the length of the hregrna line thus : — 
Length of frontal perpendicular x 100 
Length of hregrna line 
The following table gives the results obtained hy the applica- 
tion of these different methods in the case of the three skulls under 
consideration. 
Frontal Inclination. 
Index showing 
position of Bregma 
perpendicular on 
Base Line. 
Frontal 
Angle. 
Angle of 
Bregma 
Line. 
Index of 
Frontal 
Curve. 
Rutland specimen . 
29*4 
73*5° 
59° 
13 
Aberdeen , , 
38*9 
69° 
51° 
137 
Brazil , , 
33*6 
o 
O 
54° 
12 
If we examine the indices which show the position of the 
hregrna perpendicular on the base line, it becomes evident that no 
just conception can he obtained from them as to the slope of the 
forehead. Schwalbe gives the average index for the inhabitants 
of Alsace as 30 - 5 ; for the negro as 32*1 ; and for the Kalmuck 
as 32*8. In the Rutland skull the index fails to bring out the 
degree of frontal inclination ; in the Aberdeen skull it exaggerates 
it, seeing that the frontal section of the longitudinal arc is un- 
usually long ; whilst in the Brazil skull the index, compared with 
those furnished by Schwalbe, probably gives a tolerably true idea 
of the condition. 
The frontal angle affords better information on this matter. 
Amongst living races of men Schwalbe only found one skull with 
an angle as low as 73°. Had his investigation extended over a 
wider range, he would probably have found many more with a 
irontal angle at least as low. For the natives of Alsace he 
