430 DR MATTHEW YOUNG. 



Falkexburger states that in the human subject in most cases the angle NOBr is 

 a right angle and BL is parallel to BN. 



In the examination of our series of 100 Scottish skulls I shall refer to the angle 

 LBrO as the angle ' L A " and the angle NOBr as the angle " B." In the case of the 

 angle "A" it was found that the mean value was 8978° and that the range of 

 variation was from 82° to 99° ; the S.D. was 3"25 and the V. 3 - 62. The angle 

 "B" had a mean value of 89*02° and showed a range of variation from 82° to 95°, 

 the S.D. was 2'59 and the V. 2"89 ; the latter angle was thus less variable than the 

 former one. 



The angle "A" was exactly equal to 90° in 12 per cent, of the skulls, while 

 the angle " B" was equal to 90° exactly in 22 per cent. The two angles were equal, 



Fig. 14. — Diagram to illustrate Falken burger's method. 



N. Nasion. Pr. Prosthion. 



Br. Bregma. L. Br.O. = angle " A." 



L. Lambda. Br.O.N.=angle " B." 



and consequently the two lines, bregma lambda (BrL) and basion nasion (BaN), were 

 parallel in 10 per cent, only of the skulls examined. 



There is thus a tendency to parallelism of the two above lines, and we may 

 express this in another way by saying that the coefficient of correlation between the 

 two angles is *33, which indicates that there is a certain tendency for the one angle 

 to depart from its mean value in a certain direction when the other departs from its 

 mean value in that direction, i.e. either in the direction of increase or decrease. 

 It is not legitimate to correlate the angles of one triangle by the usual formula 

 owing to the influence of what is called spurious correlation, but, in the case of the 

 above two angles, we may regard them as quantities which apparently need not 

 be dependent on one another, and, as such, can have their relationship expressed 

 in the above way. 



In a South German skull which I have traced in the sagittal plane the angle " A 

 is 84° and the angle "B" 88°, while in a Negro skull the angle "A" is a 100° and 

 the angle " B" 97°. We can arrange in two parallel columns the values shown for 

 i In two angles in a short series of skulls taken from the group of 100. 



