SKELETAL REMAINS FROM PERU STEWART 



159 



definite in only 10.8 percent of the collection, whereas a corresponding 

 grade of occipital flattening occurs in at least 36.6 percent. 



In many of the extreme cases the posterior part of the skull is 

 bilobate, suggesting a deforming apparatus like that pictured by Car- 

 rion Cachot (1923, pp. 317-349) from Lambayeque. In the main, 

 however, the deformity probably could have been produced by a cradle 

 such as that pictured in plate 18 and dating from Chimu times. Such 

 a cradle would permit the infant's head to turn, and this might ac- 

 count for the asymmetry of the occipital flattening that is to be seen 

 in about 50 percent of all cases and is more common on the right than 

 on the left side. 



Table 1. — Intensity of deformity in crania from the Chicama Volley, Peru 



i By inspection. 



2 Judged to be deformed. 



Even in the extreme stages of deformity a concave frontal flatten- 

 ing seldom is seen among skulls from the Chicama Valley. Neverthe- 

 less, the widening of the skull produced here by occipital compression 

 is reflected in the proportions of the frontal bone; the frontal index 

 (frontal chord/minimum frontal diameter X 100) usually is over 

 80 and reaches as high as 94 and probably higher. On the othsr 

 hand, skulls in the National Museum from Coyungo (Nazca area) 

 not only have concave frontals but give frontal indices often between 

 75 and 80, and in one case below 75. These narrow frontal bones 

 correlate with the elongated skulls that typify the Nazca type of 

 deformity (pi. 13). 



