18-4 CHARLES R. STOCKARD AND A. L. JOHNSON 



horizontal line indicate the percentage of palate length to 

 the total length of the skull base. The direction of the curve 

 indicates that as the palatal process of the palate bone forms 

 a smaller and smaller portion of the total palate, the palate 

 as a whole forms a larger and larger fraction of the total 

 skull base. 



This curve, however, gives no indication of the types or 

 lengths of skulls in which the palate forms a higher or a 

 lower proportion of the total skull base. Are the higher 

 proportions of palate length found among the longer or the 

 shorter skulls? The curves in figure 2 of text-figure 34 were 

 plotted to answer this question. The solid line in this graph 

 represents the snout index, the dashed line the palatal index 

 and the dash-dot line the skull index. The manner of calcu- 

 lating indices is discussed beyond and need concern us only 

 briefly at present. In each of these cases the width of the 

 region involved is multiplied by 100, and this product divided 

 by the length of the region. The resulting quotient or index 

 will obviously be high if the region is wide and short, and 

 low if the region is narrow and long. The figures on the 

 vertical line represent the values of the indices and those 

 along the base line indicate proportional percentages of the 

 palatal length to total length of the skull base. 



When the snout index is high, the palatal index is likewise 

 high, as is also the skull index. Starting at the left and 

 comparing the three indices, we find that a short wide skull 

 has a palate which is proportionately wide for its length, and 

 the muzzle or snout of such a skull is comparatively more 

 abbreviated than is the skull as a whole. The first snout index 

 is 162, while the total skull index of this specimen is 103. 

 A study of the three curves throughout their extent shows 

 that in short skulls the indices for the two regions plotted 

 deviate widely from the index for the skull as a whole, while 

 in the longer skulls, with lower indices, the two regions tend 

 to show indices closely the same in magnitude as that for 

 the total skull. 



