424 DR MATTHEW YOUNG. 



Table XLIX. 



Mean frontal arc index in Scottish is 19-57 (100 specimens) 

 ,, „ Australian is 18-1 (51 ,, ) 



,, ,, Tasmanian is 18 - 7 (51 ,, ) 



Mean parietal arc index in Scottish is 20-36 (100 specimens) 



„ Australian is 20"2 (51 „ ) 



,, ,, Tasmanian is 20-5 (51 ,, ) 



Mean occipital arc index in Scottish is 14 - 81 (100 specimens) 

 ,, „ Australian is 10'9 (51 ,, ) 



,, ,, Tasmanian is 11-1 (51 „ ) 



By this means the flattening of the curve of the frontal bone as compared with 

 that of the parietal is shown to be strongly marked in the Australian, while in the 

 Scottish skull the tendency is for the two arcs to show more equal curvatures. The 

 mean parietal arc index is not greatly different in the three types, the Australian 

 showing the lowest value, the Tasmanian the highest, and the Scottish an inter- 

 mediate value. The mean occipital arc index is distinctly greater in the Scottish 

 skull than in the other two races, which show a nearly equal degree of curvature. 

 These differences in curvature of the arcs, although somewhat obscured by the 

 difference in absolute size of the types, are brought out fairly well in the super- 

 imposed tracings (figs. 10, 11, 12, 13). 



Leaving out of account for the present the upper facial triangle, which in the 

 Australian shows considerable variation from that in the Scottish skull owing to 

 prognathism being so well marked, and concentrating our attention on the brain-box, 

 it is evident, from a consideration of many of the measurements given above, that 

 some of the features on which Klaatsch laid stress in establishing a contrast 

 between the Australian and European specimens figured by him in his paper are by 

 no means constant, and that, within a homogeneous series of skulls such as the 

 Scottish one under examination, and also I believe in that of the Tasmanian, it is 

 possible to get specimens which closely approach the Australian type in these 

 characters ; in fact, the range of the values in the Scottish series includes in most 

 cases the respective values shown by the Australian ; such cases include the size of 

 many of the angles, the segments of the basi-bregmatic height, and the lengths of the 

 various chords. 



The retreating forehead of the Australian and the flattening of the frontal arc, 

 as compared with the parietal, are shown by the small mean height of the frontal 

 arc as compared with that of the parietal, the large size of the frontal angle as com- 

 pared with the parietal angle, and the well-marked difference in the two indices. In 

 the Scottish skull, as previously mentioned, the mean heights of the arcs are more 

 nearly equal, so also the mean values of the two angles, and the indices given by com- 

 paring the heights of the arcs and the lengths of the corresponding chords show only 

 a small difference in their mean value. 



Many of the typical characters, of the Tasmanian and Australian calvarise, e.g. the 



