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Proceedings of the Royal Society of Edinburgh. [Sess. 
(r = 0*9495), and the bregma angle (r = 0-9470). Based on the data of this 
investigation, these are the most valuable. Of the remaining measurements 
and indices, the first five also give values of r greater than 0'9. 
The two rejected measurements, the glabella-inion length and the 
length of the chord of the pars glabellaris of the os frontale, together with 
one other, also merit some reference. The coefficients of correlation of the 
orders given by the first two compared with the composite order of Table 
VI. were determined. That for the length of the chord of the pars 
glabellaris of the os frontale has the extremely small value of 0T152 (with 
a probable error of 0T922), while that for the glabella-inion length has 
a value of 0-2374 (with a probable error of 0-1701). The higher value of 
this latter coefficient is due in great part to the very low value (147 mm.) 
of the glabella-inion length for the anthropoid ape. Otherwise this 
measurement is at least as valueless for the present purpose as is the length 
of the pars glabellaris. 
The other measurement referred to is the calvarial height foot-point 
positional index. Of the measurements retained, it is quite the least 
valuable, with r — 0*1827. Unlike the two measurements just discussed, it 
shows no indication of approaching and then receding from a maximum 
or minimum in passing up the evolutionary scale. As far as this investiga- 
tion goes, it seems practically worthless. 
It has already been pointed out that a recalculation from more abundant 
data will probably alter in detail the relative values of the measurements 
and indices as given by the numerical values of the coefficients of correla- 
tion. When that redetermination comes to be made, the present values will, 
however, prove useful in arriving more rapidly at a sufficiently close 
approximation, weights proportional to these present values being assigned 
to the various series in determining the first of the new approximations. 
When the missing values of Table I. are all supplied, or some types at 
discretion added or omitted, each series may be calculated with a range, say, 
from zero to unity. Any newly discovered or other cranium, or group of 
crania, could then be given a new column without in any way disturbing 
the rest of the table, and its relative position for each measurement and 
index (multiplied by the assigned weight) determined. The ratio of the 
total awards to the maximum possible award would give its position. Or 
a formula could be devised on practically the same principle, the various 
terms consisting of the product of the respective coefficient of correlation 
and the ratio of the difference of the observed measurement from the 
corresponding maximum or minimum (according as to which occurred at 
the lower end of the scale) to the original total range of value. 
