400 



DR MATTHEW YOUNG. 



We observe from the table that, in the case of the male, the coefficients for frontal 

 segment and total arc and occipital segment and total arc are greater than the 

 corresponding coefficients in the female ; while, in the case of the parietal arc, the 

 coefficients for male and female are practically equal, taking into consideration the 

 greater probable error in the case of the latter. Of these coefficients the greatest of 

 all is that between occipital arc and total arc, this being slightly greater than that for 

 frontal arc and total arc, which implies a slightly greater tendency on the part of the 

 occipital arc to increase corresponding to an increase in the sagittal arc than is shown 

 by the frontal arc. The coefficient of the parietal arc and total arc is distinctly less 

 than that of the other two segments with the total arc. 



I then correlated the frontal, parietal, and occipital arcs with the maximum 

 glabello-occipital length in 100 male (" K" group) and in 100 female skulls, and the 

 results show a definite relationship between these measurements to obtain in the 

 Scottish series under examination. The results are included in the following table : — 



Table XLIV. 



Race. 



Frontal Arc and 

 Maximum Length. 



Parietal Arc and 

 Maximum Length. 



Occipital Arc and 

 Maximum Length. 



M. 



F. 



M. 



F. 



M. 



F. 



Scottish (100 M., 100 F.) 



•47±-05 



•27±-06 



•36±-05 



•38±-05 



•61±-04 



•46 ±-05 



In the first place, the correlation coefficients are in all cases smaller than those 

 between the segments of the arc and the total arc, as was to be expected. In the case 

 of the frontal and occipital correlations with the maximum length the coefficients are 

 distinctly greater in the male than in the female, whereas in the case of parietal arc 

 and maximum length the coefficient for the male is approximately equal to that in 

 the female. As is seen from the table, the correlation coefficients, in the case of the 

 occipital arc for both sexes, are distinctly greater than the corresponding coefficients 

 for the other arcs and greatest length. It would not have been so surprising had the 

 parietal arc shown the highest correlation with the greatest length, but it does seem 

 somewhat anomalous that the occipital, whose whole length does not take part in the 

 formation of that portion of the sagittal arc which forms the arc of the glabello- 

 occipital chord, should show the highest correlation with the aforesaid chord. Un- 

 fortunately, there are no comparative figures for other races, but so far as these figures 

 go they seem to show that in the Scottish series, when the greatest length of the 

 skull is increased, there is a definitely greater tendency in the male for the occipital 

 to increase in proportion ; and that the parietal shows, of the three segments, the 

 smallest tendency to increase under such circumstances. In the female, with increase 

 of glabello-occipital length the occipital arc again shows the greatest tendency to 

 increase proportionately, while the frontal shows the least tendency to increase. As 



