410 



DR MATTHEW YOUNG. 



versa, and a reference to the two diagrams (figs. 8 and 9), showing the two extreme 

 values of the zentrum angle in this Scottish series, will make this evident. In 

 the Scottish skull, as demonstrated by this series, the glabella-bregma chord shows a 

 marked tendency to be longer than the glabella-basion line, and the mean of the 

 former is decidedly greater than that of the latter ; whereas in the Tasmanian and 

 Australian series of skulls the tendency is for the glabella-basion chord to be longer 

 than the glabella-bregma chord, and the mean of the former is greater than that of 

 the latter. 



Fig. 9. — Outline of skull No. 73 of series K. This skull shows the lowest value for the angle at the zentrum, 

 i.e. 87°. Note the relatively short glabella-bregma and relatively long glabella-basion chord. (For 

 lettering see fig. 8.) 



The size of the upper glabella angle depends principally on the position of the 

 bregma, which again depends upon : — 



1. The length of the glabella-bregma line (representing the length of the frontal 



bone), and 



2. The slope or inclination of the frontal bone to the glabella-lambda line.* 

 Schwalbe (45) believes that the inclination of the frontal bone hinges on two 



factors :— 



1. The degree of elevation or depression of the bone. 



2. The degree of its curvature. 



He believes that the bregma could be displaced forwards so that the frontal 

 became more or less vertical. The extent of the displacement he measured by his 

 frontal and bregma angles ; the more open the angles, the more was the bone 

 elevated. 



* It must be noted. that the argument here applies only to Klaatsch's inscribed figure, the skulls compared being 

 oriented on the glabella-lambda line as the horizontal. In the section dealing with Schwalbe'8 data, it will be 

 demonstrated that another f;ictor of importance is involved. 



