108 
JBraui-weight and Head-size 
taken are in the case of the diameters much more precise. In many individuals 
the external occipital protuberance, even when the muscles of the neck are 
thoroughly relaxed, is difficult to localize. This is the case in the living subject, 
and still more in the cadaver, so much so that in some subjects it is impossible to 
determine its exact position. Moreover, when prominent and easily felt, there may 
be as much as 1 cm. difference between the measurement taken by one individual 
and that by another, according to whether the top or bottom of the projection has 
been taken as the starting point. The small tubercle on the tragus from which 
the measurement is taken in recording the transverse arc is also relatively to the 
centre of the external auditory meatus, a somewhat variable point. I regard these 
measurements, therefore, as less reliable than the diameters. The measurement of 
the arcs and circumference has this important advantage, however — they can 
F 
be taken by a tape measure, which can be carried in the waistcoat pocket, and they 
can thus be more readily ascertained by travellers who would be unable to carry a 
more bulky instrument. Moreover the measurement of the longitudinal and 
transverse arcs, and of the horizontal circumference, will in some cases give a truer 
estimate of size than the greatest diameters taken through the principal axes, as 
will be seen by the accompanying Fig. 2, which shows tracings of the horizontal 
circumference of two heads, one of which, represented by a continuous line, was 
narrow in the frontal I'egion, but wide in tljc parietal, whereas the other, represented 
