186 
A First Study of the Burmese Skull 
will go, through the auricular points and the apex line*. The line joining auricular 
point to auricular point is the auricular Hue of the contour, and the line perpen- 
dicular to it through its mid-point is the vertical axis MA of the transverse ver- 
tical contour. This vertical axis is divided into ten equal parts by aid of the pro- 
portional compasses, and lines parallel to the auricular line are drawn through the 
points of division. These lines are numbered from below upwards — 1 (the auricular 
line), 2, 3, 4, 5, 6, 7, 8, 9, 10; numbers 2 to 10 will not necessarily be bisected by 
the vertical axis owing to the asymmetry of the skull. Another line (/4j) is taken 
one quarter of the last section from the apex, and yet another {M\) one quarter 
of the first section from the auricular line. Ordinates are also drawn from the 
points Zi2 (J?) and ZR (L) where the zygomatic ridges are crossed (that is, from 
the line of the ridge which is a continuation of the upper edge of the zygomatic 
arch). These last three lines were added to what had been done previously, in 
order to give an idea of the shape of the contour just above the auricular points. 
(When they are omitted, and the terminals of mean 1 and 2 splined up in the type 
contour, an impression is given that the contour is traced only from the zygomatic 
ridges.) A tangent is drawn to that part of the contour which traces the roof of 
the auricular orifice, at its lowest point within about 1| cms. from the mouth of 
the opening, i.e. at the points which will have rested on the horizontal ear-rods 
on the craniophor, the rods being inserted at not more than about 1^ cms.f This 
tangent will not necessarily be parallel to the auricular line. Finally, a line parallel 
to the tangent is drawn touching the skull in the region of the apex. These two 
tangents aim at reproducing on the transverse contour the measurement taken on 
the craniophor, where a horizontal rod (i.e. parallel to the ear-rods) is brought 
down touching the skull from above, the height of it giving the OH of the direct 
measurements. The importance should be realised of adjusting the skull very care- 
fully so that the pointer passes exactly along the Hues leading into the auricular 
orifices, which give the plane in which the ear-rods lie. If, when this vertical plane 
is made horizontal, the pointer goes slightly above or below these lines, the outUne 
of the roof of the orifice may be considerably altered (since it offers a rather irregular 
surface), and consequently also the position of the tangent. 
The following measurements are now taken: length of vertical axis MA, 
length to R and L of each of the horizontals (the sum oi IR and IL being the 
interauricular diameter), distance between the two tangents, and the co-ordinates 
of the two zygomatic points. They are entered in the columns of the record for 
each contour, in the order above given, as follows: 
MA 
IR = IL 
MIL 
2R 
2L 
3R 
3L 
4R 
4:L 
5R 
5L 
6R 
6L 
* As a matter of fact I drew as much of the vertical section of the auricular passage both inferior 
and superior as my instrument permitted and these have been preserved for future study when comparative 
material is available. 
f This is the distance to which I inserted the rods. It may he advisable (see p. 182) to shorten it 
