HRDLiCKA] THE LOWER JAW 299 



western Eskimo, but of the same nature. This apparently speaks 

 strongly for the development of the Greenland type of Eskimo 

 cranium from the western. On the other hand, the type of skull 

 shown by the Eskimo child approaches much more closely than that 

 of the Eskimo adult to the type of the skull of the Mongol. 



The above are mere observations, not theories, and they carry 

 a strong indication that mostly we are still floundering only on the 

 borders of true anthropology, embracing all phases of life and devel- 

 opment, which, if mastered, would give us with beautiful definition 

 many now vainly sought or barely glimpsed solutions. 



A highly interesting feature is the relatively great development 

 in the Eskimo, between childhood and the adult stage, of the anterior 

 half of the skull or basion-nasion dimension. This augments, it is 

 seen, by even 3.4 per cent more than the length. This growth must 

 involve some additional factor to those inherent in the bones them- 

 selves and in the attached musculature, and this can only be, it seems, 

 the development of the anterior half of the brain. Evidently this 

 portion of the brain between childhood and adult life grows in the 

 Eskimo more rapidly than that behind the vertical plane correspond- 

 ing to the basion. It is a very suggestive condition calling for fur- 

 ther study, and thus far almost entirely wanting in comparative data 

 on other human as well as subhuman groups. 



THE LOWER JAW 



The lower jaw of the Eskimo deserves a thorough separate study. 

 For this purpose, however, more jaws in good condition are needed 

 from various localities, and particularly more jaws accompanying 

 their skulls. As it is, a large majority of the crania are without the 

 lower jaw, or the alveolar processes of the latter have become so 

 affected in life through age and loss of teeth that their value is dimin- 

 ished or lost. Still another serious difficulty is that the measuring of 

 the lower jaw is difficult and has not as yet been regulated by general 

 agreement, so that there is much individualism of procedures with 

 limited possibilities of comparison. 



One of the principal measurements taken on the available Eskimo 

 mandibles was the symphyseal height. This is taken by the sliding 

 calipers and is the height from the lower alveolar point (highest 

 point of the normal alveolar septum between the middle lower in- 

 cisors) to the lowest point on the inferior border of the chin in the 

 median line. 14 The results are given in the following tables. 



11 Should there be a decided notch in the middle, as happens in rare specimens, it is 

 raUonal to take the measurement to the side of the notch. 



