CATALOG OF HUMAN CRANIA — HRDLICKA 429 



The opposed behavior in the young of the two indices indicates that 

 the growth of the skull during this period is relatively greater in its 

 length and height than in its breadth. The probable cause of this is 

 the restraining effect on the breadth of the temporal muscles. 



Facial indices. — In the Eskimo infant the face is relatively low and 

 as a result so are the facial indices; but from the second year the 

 relative proportions of the face approach those of the adult. 



Facial angles. — Facial and alveolar protrusion, low in the infant, 

 gradually increases with age, the angles correspondingly growmg less 

 obtuse. The cause, of course, is the development of the dental 

 apparatus. 



Orbital index. — In general in juvenile Esldmo skulls this index is 

 very perceptibly liigher than it is in the adults; and there is no definite 

 regression in it up to adolescence and even later. After that it is 

 doubtless influenced, especially in the males, by the development of 

 the supraorbital region. 



Nasal index. — The nose in the young is relatively short but grad- 

 ually grows longer; the nasal index correspondingly is higher at first 

 but gradually, in general, becomes lower. As in all other characters 

 there are some individual exceptions. 



Dental arch. — The dental arch in the young is defective posteriorly 

 and so caimot well be compared with that of the adults. It is especially 

 short in the infant, giving low index; but from childhood on its relative 

 dimensions show no clear-cut difference from those in the adult. 



General.— The present available data show that the Eskimo infant 

 is characterized by the following conditions, as contrasted with the 

 adult: 



1. Relatively its head is markedly broader; 



2. The vault is relatively lower; 



3. The face is relatively shorter, its indices lower; 



4. Facial protrusion is lesser, facial and alveolar angles more obtuse; 



5. The orbits are relatively higher, their index higher; 



6. The nose is relatively lower, its index higher; and 



7. The dental arch is relatively shorter and its index is lower. 



U. S. SOVERNMENT PRINTINS OFFICE: 1942 



