256 
A First Study of the Burmese Skull 
is on a different plane from the rest of the surface of the occipital region, as though 
it were a mushroom-like cake placed upon the surface. Hence the caudal pole of 
the left hemisphere projects much further backward in such cases than that of 
the right, and a distinct depression is formed within the superior (cerebral) fossa 
of the squama occipitalis. Corresponding to this inner depression there is in such 
cases a marked projection of the external surface of the left side of the occipital 
bone." 
"The fulness of the left occipital pole seems to be the reason for the dextral 
bending of the superior longitudinal sinus, the flattening of the right pole allowing 
more room for the bigger sinus on that side. That this is really the case, is shewn 
by the fact that in those cases in which the right area striata spreads on to the 
caudal surface to a greater extent than it does on the left side, the right occipital 
pole and the right occipital squama become more prominent and the superior 
longitudinal sinus turns to the left. Again in those cases in which the occipital 
poles are symmetrical, the superior longitudinal sinus usually bifurcates, one half 
going to each lateral sinus." 
It seemed possible that the data I had already obtained might serve to give 
some measure statistically to the interesting associations thus suggested. It was 
naturally impossible to obtain from our material any measure of the association 
of extended area striata on one side, with main lateral sinus on the other. It is 
unhkely that the size of the area striata will be perfectly represented by a depression 
in the inner surface of the occipital (fossa cor. striatae) : as Professor Elhot Smith 
is careful to say, "«s a rule this lateral part of the area striata is on a different 
plane from the rest of the surface of the occipital region," and where it does not 
"resemble a mushroom-like cake," there will be no corresponding fossa. Probably, 
however, there would be a correlation between the two. Similarly, the occipital 
grooves are not bound to be an exact reflex of the longitudinal and lateral sinuses, 
though perhaps manifesting correlation. Again, the occipital bone is of very vary- 
ing thickness, and an interior depression is not necessarily accompanied by an 
exterior projection within limits of say 1 to 2 mms. though again there might be 
a certain degree of correlation between them over a series. Lacking perfect associa- 
tion between these different stages, it would be impossible to form unassailable 
conclusions as to the conditions obtaining in the brain and sinuses from an examina- 
tion of the exterior of the skull. Again, assuming correlation, but not almost perfect 
correlation, to exist between these different variates, it is by no means needful, as 
the theory of correlation shows, when C is correlated with B and B again with A 
and when D is correlated with E, for a correlation between C and D to involve a 
correlation between A and E ; but it is worth examining whether A and E (exterior 
occipital asymmetry and interior direction of grooves) which we can observe are 
really correlated. The presence or absence of such correlation unless it were almost 
perfect would not, however, enable us to predict a relationship of C and D (area 
striata to direction of superior longitudinal sinus). 
It is with data concerning exterior occipital asymmetry, and the direction of 
the main inner groove that I was furnished, and on these based a contingency 
