A CONTRIBUTION TO THE STUDY OF THE SCOTTISH SKULL. 



365 



I am quite well aware that the index obtained from the mean values of the 

 absolute measurements is not exactly equal to the mean index, as the latter depends 

 to some extent on the coefficients of correlation and variation of the absolute 

 measurements. The above approximate results, however, for female and male, which 

 are practically equal, would seem to show that there is no marked sexual difference in 

 the proportions obtaining between the parietal and the occipital and frontal arcs. 



I have instituted, in considerable detail, a comparison between the principal mean 

 values of the various dimensions of the male and female groups in Turner's series 

 and the corresponding groups in the series at present under investigation, because it 

 is only in that important memoir that I can obtain material for comparison. While 

 there are many slight differences in the mean values of the dimensions in the two 

 series — differences by no means negligible, but probably partly due to the " personal 

 equation," — the feature that stands out pre-eminently, and in a sense overshadows 

 the minor differences, is the divergence in value in the greatest parieto-squamous or 

 maximum breadth, which is distinct and definite in the female groups, but exception- 

 ally well marked in the male groups. To this, and not to a difference in the greatest 

 length, is due the difference in the cephalic index. There is a marked tendency 

 to dolichocephaly in the series under investigation, whereas, in the series examined 

 by Turner, there is a distinct tendency towards brachycephaly. The diminution in 

 cubic capacity in the present series compared with Turner's series is undoubtedly 

 a real difference, not entirely due to the personal element but dependent largely 

 upon the smaller maximum breadth. 



In the following table I have arranged the mean indices according to their classes 

 for both male and female groups : — 



Table XX. 







Class. 





Index. 







Remarks. 









M. 



F. 





Cephalic index 



Height index . 

 Height-breadth index 

 Maxillo-facial index . 

 Orbital index . 



Dolichocephalic 



Metriocephalic 

 Platychamsecephalic 

 Leptoprosopic 

 Mesosemic 



Mesaticeplialic (lower divi- 

 sion) 

 Metriocephalic 

 Platychamsecephalic 

 Leptoprosopic 

 Mesosemic 



F. show distinctly greater tend- 

 ency to brachycephaly 



Both sexes practically similar 



Male nearer hypsistenocephaly 



Sexes practically alike 



F. index greater (on border of 

 megaseme class) 



Nasal index 



Mesorhine 



Mesorhine 



F. higher index value 



Gnathic index . 



Orthognathic 



Orthognathic 



Sexes nearly alike. M. slightly 

 higher mean index 



Palato-alveolar index 



Mesuranic 



Mesuranic 



F. higher index than M. 



(See Plates I, II, and III for examples of typical male and female skulls from the series.) 



