Eskimo Osteology. c47 



The Index of Height of the Bbegma above the Glabella-Inion Line 



Owing to the fact that the crania could not be sectioned in the mesial plane, 

 the three basal angles and the calvarial height index could not be calculated. 

 As a substitute for the latter the writer devised the index which forms the 

 subject of this paragraph. In estimating it, the perpendicular height of the 

 bregma above the glabella-inion line was compared with the length of the 

 latter. The glabella-inion length for each skull was first of all measured off 

 on paper. The glabella-bregma and inion-bregma chords were then measured 

 off with drawing compasses and of course the point of meeting of these chords 

 gave the position of the bregma. A perpendicular line dropped from the latter 

 on to the glabella-inion line then gave the bregmatic height drawn to scale. 

 Its length was estimated, multipied by a hundred, and divided by the glabella- 

 inion length. The bregmatic height would of course be a little less than the 

 calvarial height, and therefore it was not surprising to find that in this index 

 the results, with one exception, were all under 50. The index of calvarial height, 

 on the other hand, is always well over 50 in the higher races of modern mankind, 

 In these Eskimo crania the bregmatic height index varied from 52-2 to 44-7 

 in the males and from 48-5 to 43-7 in the females. It will thus be observed 

 that this index displays a very moderate degree of racial variation, when com- 

 pared with the vagaries of some of the cranial indices. 



It may be noted here that the height of the bregma above the glabella- 

 inion line ranged from 92-3 mm. to 80-3 mm. in the male crania and from 

 87-5 mm. to 70 mm. in the female. 



The Bregmatic Angle 



This angular cranial measurement has only come into its own within recent 

 years as a factor of prime importance and significance in craniology. It is 

 utilised to demonstrate the degree of expansion of the frontal cranial arc. One 

 usually finds the briefest descriptions in textbooks regarding its exact method 

 of application, and indeed, it appears to have been mainly used in the study 

 of the calvaria of fossil man. Schwalbe(i^) was one of the pioneers in its utiliza- 

 tion and took full advantage of its value in his classic duty of the Neanderthal 

 calvaria. For the present research his plan of procedure was adopted, this 

 being the angle included between the glabella-bergma and the glabella-inion 

 lines. 



In these Eskimo crania the bregmatic angle varied from 58-5° to 53-5° 

 in the males and from 60° to 51-5° in the females. The male crania were thuS 

 within the range of variation for modern Hominidse, which is given by Duck- 

 worth ('") as from 66° to 53°, while the female series sank slightly below this. 

 It would thus be interesting to note the effect of sex upon this angle. The 

 average of the bregmatic angle was 55-5° for the male crania and 54-2° for the 

 female crania. The writer was surprised to find that the general average of 

 these was practically the same as that found by Berry and Robertson(i) in a series 

 of one hundred aboriginal Australian skulls, namely 54-7°, and slightly lower 

 than the average obtained by the same observers in forty-five aboriginal Tas- 

 manian skulls (namely 56°). Moreover, the average for these Eskimo skulls 

 compared unfavourably with the results obtained by the writer(*) in two low 

 type Melanesian skulls (55° and 59°), and also with that of a Micmac North 

 American Indian skull (60°) recently recorded by the writer. (^) Indeed the 

 Eskimo average was comparable to that of a fossil type like the Cr6-magnon(") 

 cranium (with a bregmatic angle of 54°). 



