46c Canadian Arctic Expedition, 1913-18 



In passing, it is interesting to watch the reduction of this index to zero 

 in the anthropoid apes. In the gorilla for example, it is non-existent owing to 

 the fusion of the temporal lines in the mesial plane of the cranial vault to form 

 the prominent crest along the line of the sagittal suture that is so pronounced 

 in this animal. 



The Gonio-Ztgomatic Index 



This is an index that has been very little exploited by anthropoligists, and 

 therefore the data regarding it are rather scanty. The idea involved in its 

 application is to compare the width between the angles of the mandible with 

 the inter-zygomatic breadth. It may be noted that the Eskimo skull furnishes 

 the highest known average for this index amongst modern Hominidae, and 

 DuckworthC'") gives the average for the race as 82-5. The average for these 

 crania was 82 • 8 which practically accorded with the above result. It is worthy 

 of mention that in only one skull did the index fall below 80, while the maximum 

 was represented by 88-2. 



The Fronto-Parietal Index 



This cranial index has been applied chiefly to the calvaria of fossil man, 

 and has not been elaborated much in reference to the crania of modern Hom- 

 inidae. Indeed, the writer appears to be the only observer who has utilized 

 it to any large extent (* ^&'), though it is possible he may stand correction on 

 that point. The index varied from 77 • 1 to 66 ■ 4 in the male crania, and from 

 75 to 67-9 in the female. Thus in one male skull the minimum post-orbital 

 diameter was only 66-4 p.c. of the maximum parietal breadth. One will appre- 

 ciate how low an ebb this is, upon recollecting that the corresponding index 

 for such a lowly evolved type as the Java calvaria {Pithecanthropus erectus) 

 is 65-4.(") This remarkable post-orbital constriction is quite a feature of the 

 Java calvaria, as well as of the crania of the anthropoid apes, when examined 

 from above. Again, it was noted that ten of the female crania and six of the 

 male crania possessed fronto-parietal indices of a lower grade than that of the 

 primitive type of skull represented by Neanderthal man. To carry the compari- 

 son further it was ascertained that many of these Eskimo skulls compared 

 unfavourably with the Melanesian type in regard to their fronto-parietal indices, 

 thus bringing them down to the level of one of the lowest types of living mankind. 



On studying the crania of the higher types of modern Hominidae from above, 

 it is found that there is a progressive attempt to fill out the general contour and 

 more particularly to obliterate the post-orbital constriction as much as possible. 

 The result is a gradual improvement in the fronto-parietal index which in the 

 European type of skull approximates to 90. 



There must be some subtle cause for the creation of this low fronto-parietal 

 index, which places the Eskimo skull, in other respects a well-developed one, in 

 a comparatively lowly position amongst modern Hominidae. The suggestion 

 the writer would like to offer is that the Eskimo, owing to his characteristic 

 dietary, has to commence his strenous masticatory habits at an early stage in 

 life. The result is, that his skull becomes compressed laterally by his powerfully 

 developed temporal muscles, while still in the pliable condition of childhood. 

 The effect of this would be to create a marked post-orbital constriction and 

 this would provide the essential element for the reduction of his fronto-parietal 

 index. 



