1905 - 6 .] 
Report on Two Crania. 
299 
Inclination of the Frontal Bone . — The slope of the frontal plate 
of the frontal bone must always he regarded as possessing a very 
considerable degree of anthropological interest. As we descend 
from the higher to the lower races, the general tendency towards 
an increasing degree of backward slope of the forehead becomes 
manifest. It has already been stated that the obliquity of the 
frontal region of the calvaria constituted a striking characteristic 
of the Butland specimen. 
Fig. 1 . — The Rutland Cranium. Tracing of the mesial longitudinal arc 
obtained by the American periglyph. Reduced by one-half. 
Several methods may be adopted for the purpose of expressing 
more or less accurately the degree of frontal inclination. Three 
of these which were followed by Schwalbe in his study of the 
cranium of Pithecanthropus may in the first instance be applied to 
the Rutland specimen. The first step in each of these methods 
consists in obtaining an accurate tracing of the mesial longitudinal 
arc of the cranium. This may be done by the American periglyph, 
and upon the tracing a base line should be drawn from the inion 
to the centre or most prominent point of the glabella. 
(1) Schwalbe’s first method consists in dropping a perpen- 
dicular from the bregma so as to intersect the base line at right 
