434 DR MATTHEW YOUNG. 



1 do not propose to analyse these measurements at length, as I did in the case of 

 i lie less-known method of Klaatsch, but shall merely endeavour to develop the 

 conclusions to which they point when taken along with the data already established. 

 It has already been seen (Table XXI) that while the selected series of 100 West 

 Scottish skulls has the same mean cephalic index as the Tasmanian and a rather 

 higher index than the Australian, the mean altitudinal index in the first is slightly 

 lower than in both the others because, while the Scottish skull is slightly higher 

 than the other two, its relative increase in length is more marked. 



Showing as it does a greater mean value for the three principal dimensions, the 

 West Scottish skull has a considerably greater capacity than the other two types. 



As tested by Schwalbe's measurements, the West Scottish skull has a con- 

 siderably greater calvarial height and the vault above the glabella-inion line is 

 longer, broader, and higher than in the Tasmanian and Australian. Coincidently 

 with this the frontal bone is on the average longer, more curved, and steeper, as is 

 shown by a comparison of the length of the frontal chord, the curvature index of 

 the os frontale, the size of the bregma angle, and the angle of frontal curvature in 

 the three types ; the parietal bone is on the average approximately equal in length 

 in the three races, and presents the same proportionate degree of curvature in all, as 

 was also demonstrated by the equality shown for the three types by Klaatsch's 

 parietal-arc-height index. The occipital bone in the Scottish skull is less acutely 

 inclined to the glabella-inion line (the lambda angle being larger) and is flatter below, 

 as the opisthionic angle is distinctly smaller than in the Australian and Tasmanian. 

 Now by Klaatsch's method it was shown that in the West Scottish skull the lower 

 part of the basi-bregmatic height was on the average longer than the upper segment, 

 the two segments were equal in the Tasmanian, while in the Australian the upper 

 segment was greater than the lower. The mean value for the upper segment was, 

 however, practically identical in the three types. Again, the lambda-inion chord was 

 considerably longer in the Scottish than in the two lower types. This last point tends 

 to explain the greater length of the lower part of the basi-bregmatic height, and also 

 why Schwalbe's calvarial height is greater in the West Scottish skull (fig. 15). 



The greater development of the supra-inial portion of the occipital bone in the 

 mean Scottish than in the mean Australian skull also explains the fact that while 

 the mean upper glabella angle is smaller in the former than in the latter, the bregma 

 angle is smaller in the latter than in the former. The frontal bone is more inclined 

 in the Australian than in the Scottish skull when the glabella-inion plane is taken as 

 the horizontal, but apj)arently less inclined when the glabella-lambda line is taken as 

 the horizontal. The vault in the Scottish skull is, in short, deeper posteriorly ; the 

 lambda is more elevated above the glabella-inion plane ; the glabella-lambda line 

 does not lie in the same relative plane as the Australian (fig. 15). 



If therefore supposing, for the moment, the West Scottish brain case to represent 

 the evolved or terminal phase of a brain box of the Tasmanian or Australian type, 



