THE EVOLUTION OF THE EYEBROW REGION OF THE FOREHEAD. 285 



be taken as being comparable with those indices obtained from measurements of the 

 skull, but there is reason to believe that if the calvaria of Boco were denuded of 

 the scalp covering it would give an index at least as high as that of the Neanderthal 

 cranium. 



But what is the value of this glabello-cerebral index of Schwa lbe ? Can we rely 

 upon it giving a true and proper idea of the relative extent and degree of projection of 

 the pars glabellaris of the cranium ? I do not think that we can, and I look upon the 

 figures given above as being of little value, and in certain respects misleading. If the 

 mesial length of the frontal bone, measured either by the tape or the callipers, from the 

 nasion to the bregma were relatively (even approximately) the same in different skulls, 

 some reliance might be placed on the index ; but when we find in three skulls so similar 

 in the degree of glabellar projection as the Neanderthal, Spy 1, and Eiverina the total 

 frontal length, as ascertained by the tape, so very different as 133 mm., 120 mm., and 

 147 mm. respectively, it is evident that in these cases the index expresses variations in 

 the length of the cerebral part of the frontal bone more than variations in the length of 

 the glabellar part. Indeed, no index is necessary. The proper comparison to institute 

 is one between the absolute measurements of the glabellar part made by the tape over 

 its curvature from nasion to ophryon in different skulls. When this is done in the 

 crania under consideration we obtain the following figures, and from these we can best 

 realise the extent and degree of glabellar projection : — 



New South Wales cranium (xxix. 



B. 1) . 



. 31 mm. 



Spy No. 1 





• 40 „ 



Riverina skull (xxix. B. 12) 





■ 41 „ 



Neanderthal cranium 





■ 43 „ 



Boco (over scalp tissues) 





• 50 „ 



We are thus enabled to conclude that the high degree of glabellar development which 

 is seen in the Neanderthal group, and which in it constitutes a distinct and definite racial 

 character, may nevertheless be attained as an occasional variation in certaiu individuals 

 of other races — notably the Australian race. 



GtIUFRIDa-Ruggeri (4), in a suggestive and well-reasoned paper, likewise expresses his 

 dissatisfaction with Schwalbe's glabello-cerebral index. He refers to the variability in 

 the position of the bregma due to differences in the form of the coronal suture,* and 

 then he goes on to remark : " Even the position of the nasion varies according as the 

 fronto-nasal suture is semilunar, triangular, or horseshoe-shaped, and this exercises an 

 influence on the length of the glabellar chord. I have obtained higher indices in certain 

 Melanesian skulls in which the bregma was not much displaced backwards." He gives 

 five examples in which the index varied from 30*2 to 33*3, and then remarks : " Finally, 

 in the skull 760, which is one of the most interesting in the Anthropological Museum in 

 Rome, I obtained an index of 39*7, to which I would draw the attention of Professor 

 Schwalbe." 



* This is merely another way of stating that the variations in the position of the bregma are due to variations in 

 the extent of the frontal field of the cranial wall. 



