A CONTRIBUTION TO THE STUDY OF THE SCOTTISH SKULL. 



417 



with a mean value of 130'1 mm., S.D. 5'27, V. 4'05. In the Scottish series the basi- 

 bregmatic height varies from 123 to 147 mm., with a mean of 133'7 mm., S.D. 5'47, 

 V. 4'09. In this dimension also evidence of the difference in size of the skulls in 

 the two series is marked, while the standard deviation and the coefficients of 

 variability are very similar in the two series. 



From a comparison of the coefficients of variability, with regard to this measure- 

 ment and,, the previous one, it is shown that the basi-bregmatic height is in both 

 series more variable than the glabella-lambda length. The measurement given by 

 KLAATSCH'for an Australian specimen is 133 mm., which is greater than the mean 

 value of the Tasmanian, smaller than the Scottish mean value, but within the range 

 of both; while the mean of Berry's series of 90 Australian skulls is 130 mm., and 

 the range of variation shown is from 116 to 144 mm., S.D. 6'50, V. 5'00. 



As regards the two segments of the basi-bregmatic height in the Tasmanian 

 series of male skulls, the upper segment, which is the measure of the elevation of 

 the glabella-lambda arc, varies from 54 to 73 mm., with a mean value of 65*4 mm. ; 

 the lower segment varies from 55 to 75 mm., with a mean value of 65 mm. The 

 means of the upper and lower segments are thus in the series examined nearly equal. 



In the Scottish series the upper segment varies in length from 56 to 76 mm., with 

 a mean of 65 '75 mm. ; the lower segment varies from 55 to 82 mm., with a mean of 

 67'85 mm. The mean value of the lower segment is thus greater than the mean 

 value of the upper segment, and in this respect approximates to the measurements 

 of the Australian skull as figured by Klaatsch and of another measured by myself. 

 The basi-bregmatic height of this Australian skull is 133 mm., the upper segment is 

 59 mm., the lower 74 mm. The mean value of the basi-bregmatic height in the 

 Scottish series, as stated above, is 133*7 mm., which is approximately equal to the 

 height of Klaatsch's Australian skull, so that both the values of the two segments of 

 the Australian fall well within the ranges of variation shown in the corresponding 

 segments in the Scottish series of skulls. 



Noting a few measurements of these segments in skulls of the Scottish series, 



we can compare them with the condition found in Klaatsch's Australian in the 



following way : — 



Table XL VII. 



Australian. 



Scottish. 



Basi-bregmatic 

 Height. 



Upper Segment. 



Lower Segment. 



Basi-bregmatic 

 Height. 



Upper Segment. 



Lower Segment. 



133 



59 mm. 



74 mm. 



(a) 133 mm. 

 (6) 133 „ 



(c) 133 „ 



(d) 142 „ 



(e) 146 „ 

 (/) 140 „ 



63 mm. 



64 „ 



62 „ 



63 „ 



64 „ 

 64 „ 



70 mm. 

 69 „ 



71 „ 

 79 „ 

 82 „ 

 76 „ 



