CRANIOLOGY OF THE PEOPLE OF SCOTLAND. 595 



the glabella. The observations of A. Logan Turner # have shown that the frontal 

 sinus is not limited to the region of the glabella and supraorbital ridges, but extends in 

 a large proportion of skulls above the ophryon, so that the influence of the sinus in 

 adding to the cranial length is by no means eliminated by selecting the ophryo- 

 occipital in preference to the glabello-occipital diameter. (Figs. 25, 26, PI. V.) 



Breadth. — The greatest parieto-squamous breadth was obtained in one hundred and 

 seventy-four crania, viz., one hundred and fourteen men and sixty women. In the 

 men the broadest skull was 159 mm., and twenty-four crania were between 150 and 

 159 mm. The narrowest male skull was 130 mm., and twenty-six skulls ranged from 

 130 to 139 mm. In the women the broadest skull was 153 mm., two specimens being 

 of that diameter. The narrowest skull was 128 mm., and thirty-six specimens ranged 

 from 130 to 139 mm., whilst nineteen were between 140 and 150 mm. The mean 

 breadth of the male crania was 149*3 mm., that of the female was 138 mm. This 

 diameter approximates to the greatest breadth of the cerebrum in each individual. 



In addition to the parieto-squamous breadth the tables contain two breadth measure- 

 ments of the frontal region, as well as the asterionic diameter which gives the breadth 

 of the occipital bone between its lateral angles. As a general rule the frontal Stephanie 

 diameter materially exceeded the minimum frontal, though in a few instances it was 

 not more than from 2 to 8 mm. greater. These dimensions give an approximation 

 to the width of the frontal lobes of the cerebrum. Twenty-three crania had a persistent 

 frontal suture, viz. sixteen males and seven females. The metopic crania as a rule ex- 

 ceeded in their frontal diameter the skulls of the corresponding sex from the same locality 

 in which the frontal suture was ossified, and confirmed the view entertained by 

 many craniologists that persistence of the frontal suture contributes to an increase 

 in the transverse diameter of the skull and brain in that region. 



The asterionic diameter, except in one skull, was greater than the minimum frontal, 

 but as a rule it was less than the Stephanie, though there were several exceptions. 

 This diameter may be regarded as giving an indication of the breadth of the cerebellum. 



Cephalic Index. — As is well known, this index expresses the relation which the 

 greatest parieto-squamous breadth of a skull bears to its maximum length, the length 

 being regarded as =100, and the formula is as follows: 



greatest breadth x 1 00 

 maximum length 



The index was obtained in one hundred and seventy-four skulls, one hundred and 

 fourteen of which were males and sixty were females. The index showed a great 

 range of variation from 87 "2 to 68 "2. The mean length-breadth index in the men was 

 77 '4, in the women 77 "2. Both sexes, taken collectively, had essentially the same mean 

 index, and were in the middle of the mesaticephalic group. If we follow the customary 

 arbitrary grouping of crania according to the length-breadth or cephalic index, we find 



* Accessory Sinuses of the Nose, p. 105. Edin., 1901. 

 TRANS. ROY. SOC. EDIN., VOL. XL. PART III. (NO. 24). 4 t 



