GORRESPONDING SOCIETIES. 3393 
The ratio of the head-breadth to the head-length has been found to be 
a very valuable index of race. This, when expressed as a percentage, is 
termed the cephalic index, and races having a high cephalic index are said 
to be brachycephalic, those having a low cephalic index dolichocephalic, 
and those with a medium cephalic index mesocephalic. 
In a map showing the geographical distribution of cephalic indexes 
among the various races of the earth it will be seen that the grand centre 
of brachycephaly is in the mountainous regions of Central Asia, and that 
it spreads with reduced intensity through Asia Minor and the Alpine 
regions of Central Europe. The native Indian tribes of America are mostly 
brachycephalic, while dolichocephaly is practically universal in Africa. 
In the south and north of Europe the populations are inclined to dolicho- 
cephaly. 
These general facts give us a datum-line for the determination of the 
probable racial affinities of the prehistoric races of Britain. 
I show a chart of the average head-dimensions of the known prehistoric 
races of Britain. The position of each race on the chart is determined by 
using its average length and breadth of head as a kind of latitude and 
longitude, the diagonal lines showing the cephalic indexes. 
The earliest skulls found in Britain (with the éxception of one solitary 
palzolithic specimen) belong to the neolithic or late Stone Age. This race 
is represented on the chart by two groups, one measured by Davis and 
Thurnam and the other by Schuster; both these groups are dolichocephalic. 
Following the neolithic race, at the beginning of the Bronze Age, a short 
hyper-brachycephalic race, with a cephalic index of 86, entered Britain. 
Knowing what we do about the stability of the physical dimensions of races, 
it appears to be impossible to believe that this race was derived from the 
neolithic race. Its nearest affinities, as far as is known, are with some of 
the brachycephalic mongoloid races of Asia. 
Coming after this short hyper-brachycephalic race of the early Bronze Age 
we have a tall brachycephalic race of the later Bronze Age (the round barrow- 
men), which from its position on the chart may well be a blend of the two 
previous races. Then we have the Saxon type of the Iron Age, which closely 
resembles the modern Scandinavian type, as we should naturally expect 
from historical evidence. 
Thus we see that where historical and anthropometric evidence overlap 
they agree. This gives us some confidence in the anthropometric evidence, 
which may fairly claim that it contributes an important part of the light 
that relieves the long night before the dawn of history. 
Traces of these prehistoric races ought to be found in the living popula- 
tion of the British Isles, and, as far as measurements have been made, 
this is found to be the case. Comparatively few measurements of the 
living races have, however, been made, and this is one of the questions of 
the greatest scientific interest which would be solved by a National Anthro- 
pometric Survey. 
If the Corresponding Societies were to undertake such a survey they 
might be able to tell us whether the cephalic index of the population is 
higher than the average in the districts where the hyper-brachycephalic 
skeletons of the early Bronze Age have been found—for example, in Wales 
and on the east of Scotland from the Forth to the Orkneys. cSisy 
Again, we should look for a dolichocephalic type, tall and fair, in the 
regions which history tells us were conquered and colonised by the Anglo- 
Saxons. The extent to which these characteristic traits of the Teutonic or 
North European race have been modified will give a fair estimate of the 
amount of admixture with other races or of the influence of known changes 
of environment. ‘ et. 
These illustrations may give you some idea of the immense scientific 
interest of extensive measurements of the living population. 
