222 
A First Study of the Burmese Skull 
Finally, as regards the general appearance of greater massiveness and rugged- 
ness in Group A: this is confirmed to some extent by the weight (W. in grs.). 
Weight, it is true, does not depend only on size, but also on thickness of the bone*; 
but here, again, since exterior unevennesses and protuberances are by no means 
bound to correspond with interior excavations, it is probable that the smoother 
skulls are also the thinner on the whole, and that a more rugged appearance is 
associated to some extent with thickness. 
Let us turn now to other characters than those which were considered in group- 
ing, and first the main proportions of the skull. The Burman Group is definitely 
broader-headed than Group C for c? and ?, the difference in maximum breadth (B) 
bei-ng greater in the case of the females (seven times the probable error) than with 
the males (three times). It is also shorter-headed, as is seen by the three length 
measurements L, L' and ¥ . The result of both facts is that Group A has a higher 
cephalic index {lOOB/L or lOOBjL') in both sexes, being brought well within the 
brachycephalic category, while Group C is merely mesocephalic. The difference 
between the indices in both sexes ranges from about four to sixteen times its prob- 
able error. 
Associated with the greater maximum breadth in Group A, we find in both 
and ? greater forehead breadth (B'), and the greater breadth of face, nose and 
nasal bridge to which we have already referred. It is not, however, accompanied 
by any significant difference in breadth of orbit (0^, R and L), of palate (G2), or of 
foramen magnum {fmb). Nor, on the other hand, is the shorter head-length in 
Group A associated with a significantly shorter foramen magnum (fml) or palate 
((?/ and (?i). 
The indices for these two {fmb j fml and G^IG-^ likewise give no definite sign of 
differentiation. 
When we consider the measurement for height {H and H') we do not find any 
such marked differences between the two groups as in length. Such difierence as 
there is, is in ojjposite sense for the two sexes, but in neither case is this 2-5 times 
the probable error, and cannot be counted as significant. Nor do we find any 
significance in the differences between the means of the two groups for height 
above the auricular passages {OH); in height of orbit {O.2R, O^L), upper-face height 
{G'H), and height of nose {NH, R and L), Group C shows a definite advantage, 
but for females only. 
The orbital index {OJO^, R and L) indicates that the Burman women are 
rounder-eyed than those of Group C. The men of the two groups are much alike. 
As to the cranial indices in which height is a factor, Group A has a higher 
value for breadth over height {B/H), as we should expect; but the females alone 
of Group A have a significantly higher value for height over length {H/L and 
H IL'), the difference in males being negligible. The combined index {B — H)IL shows 
a dift'erence of about six times the probable error in both <S and ?. This index places 
* And again on the manner in which the skull has been i^reserved. In the present case the same 
average conditions of preservation apply to the different series. 
