Kathleen V. Ryley and Julia Bell 
401 
It will be seen that the catenary assumption as to the bridge of the nose, 
notwithstanding the relatively high correlations of a and a, is not very satisfactory * 
If it were, the best fitting or regression line would be simply a = a'. Thus the 
regression coefficient should be unity and the constant term zero. This is roughly 
true for English females, less true for English and Hindoo males, and approximately 
the case in Congo females and Gaboon (1864) males. For the anthropoids the 
deviations are very considerable, and this is also true for the Veddahs. The 
catenary form of the nose appears to be an impression largely based on familiarity 
with the higher racial types. Thus the mesodacryal subtense index a can only 
be deduced from the mesodacryal arcual index /3 for individuals of the higher 
races. At the same time Table IV shows that the racial value a of a as 
deduced from /3 is very little in excess of the true value for a number of races, 
and we conclude that the hypothesis has greater value for interracial than for 
intraracial comparisons"!". 
(4) On the Simotic and Mesodacryal Indices. 
If we are going to use these indices as a racial scale, it becomes of some 
importance to determine which provides the better classification. Unfortunately 
the simotic index cannot be determined for the Orang-utan. But an examina- 
tion of Table IX shows that the Chimpanzee is placed at one end, the Gorilla at 
* It serves excellently, however, as a control of individual measurements, and when a' is not 
approximately a it is always worth reconsidering the measurements involved. 
f In order to obtain the values of a' from those of /3 for the catenary hypothesis in the case of the 
Chimpanzee and Orang-utan, the table published in Biometrika, Vol. vin. pp. 338 — 9, had to be 
somewhat extended. The values in Table VII below were obtained. 
TABLE VII. 
Supplementary Tables for Subtense Mesodacryal Index a as calculated 
from the arcual value ft on the Catenary Hypothesis. 
(A) Values of a. 
|8 
■o 
■1 
•0 
■4 
~5 
■6 
'7 
■s 
•9 
6 
15-3 
15-4 
15-6 
15-7 
15-8 
16 -0 
16-1 
16-2 
163 
KJ-5 
7 
16-6 
16-7 
16-8 
17'0 
17-1 
17-2 
17-3 
174 
17-6 
17-7 
8 
17-8 
17-9 
18-0 
18-1 
18 3 
18-4 
18-5 
18-6 
18-7 
18-8 
9 
18-9 
19-1 
19-2 
19-3 
19-4 
19-5 
19-6 
19-7 
19-8 
19-9 
10 
20-0 
20-1 
20-2 
20-3 
20-4 
20-6 
20-7 
20-8 
20-9 
21-0 
11 
214 
21-2 
21-3 
21-4 
21-5 
21-6 
21-7 
21-8 
21-9 
22-0 
12 
22-1 
22-2 
22-3 
22-4 
22-5 
22-6 
22-7 
22-8 
22-9 
23-0 
