SKELETAL REMAINS FROM PERU STEWART 163 



These findings have suggested to me that by removing the most 

 brachycranic and presumably slightly deformed skulls from the 

 "undeformed" Peruvian series, until a more natural variability is 

 obtained, I could obtain a truer undeformed range, as well as a truer 

 mean. Acting on this thought, I have reduced arbitrarily the male 

 range from 68.2-90.5 to 68.2-82.6. This deletion results in the follow- 

 ing distribution : 



Ql ass Vew series Removed 



G5-G9.9 1 



70-74.9 7 



75-79.9 25 -- 



80-84.9 I 7 b 



85-89.9 6 



90-94.5 J- 



Total 50 15 



The new series gives a standard deviation of 3.29 for the cranial 

 index and a mean of 77.8. The length then becomes 177 mm. (S. D. 

 5.53) and the breadth 138 mm. (S. D. 4.62). These means are close 

 to those of the Mochica series given in table 2 and probably approx- 

 imate the true undeformed type. 



Since we have definite evidence now from this northern coastal 

 region that cranial deformity is linked with culture, it is desirable 

 to know whether the custom of deforming the head was introduced 

 without a physical change in population, or whether there was a 

 population replacement by a physically different people who practiced 

 this custom. This is the second problem listed above. In attempting 

 to solve this I have measured a series of 50 deformed Chicama Valley 

 skulls of each sex for additional comparison with the miscellaneous 

 undeformed series. The measurements have been restricted to those 

 that I have assumed to be least affected by deformity, which means 

 chiefly facial measurements. In table 4 I give the differences between 

 the means of these two series together with their probable errors and 

 X p. e.'s. 



Of the 12 measurements and indices here listed, 6 show higher and 

 4 show lower means for the deformed group in both sexes. The two 

 remaining measures show very small differences that vary in opposite 

 directions in the two sexes. Two of the higher means in the males 

 and three in the females appear to be significantly different ; that is, 

 they exceed three times their probable errors. It is noteworthy as 

 regards the higher measurements in the deformed group that face 

 height and orbital height are increased significantly in both sexes, 

 while there is also an increase in nose height in both sexes that 

 approaches significance at least in the males. This increase in the 

 absolute heights of the face, orbits, and nose cannot be reconciled 

 with the type of deformity present. 



