128 
Cranial Type-Contours 
Thus the three contours require 60 measurements to be made in order that 
they may be effectively reproduced from the plotted points. 
Illustrations of the complete system of measurements made on the individual 
sagittal contour in the Biometric Laboratory are given in Figs. I and II. Fig. I 
represents the fine head of Thurtell the murderer from the Royal College of 
Surgeons. Fig. II the head of one of the long series (2000 crania) of Egyptians 
(600 — 300 B.C.) in the Biometric Laboratory. iV=Nasion, Gl = Glabellar point, 
B = Bregma, \ = Lambda, 7 = Gamma, the occipital horizontal point, / = Inion, 
Op. = Opisthion, A ur. = Auricular point, Bas. = Basion, A Iv. = Alveolar point, 
Suborb. = infra-orbital point. Suborb. to Aur., if joined by a line, gives the 
Frankfurt Horizontal Plane. Ny is the horizontal plane through the nasion. The 
angles N, B and A are the nasal, basilar and alveolar angles of the fundamental 
triangle NBAlv. P is the profile angle measured from the Frankfurt horizontal. 
<f> is the angle between the glabella-inion and glabella-bregma lines, <f>' the angle 
between the nasion-inion and nasion-bregma lines. There are three interesting 
subtenses s, x and y. y is the maximum subtense or height of the calvaria 
measured from the glabella-inion line. A subtense may also be taken between the 
nasion-lambda line and the most distant point of the calvaria (in the median 
contour). It does not, however, differ very widely from the bregmatic subtense x, 
the perpendicular from the bregma on the nasion-lambda line ; it is drawn but 
not lettered on Figs. I and II. On the other hand the bregmatic subtense s, or 
the perpendicular from the bregma on the glabella-inion line, differs widely from 
the maximum subtense y, and this difference is of interest. 
(3) These sixty measurements, having been made on each of 50 to 100 sets 
of contour drawings, were arranged in columns, one for each measurement. These 
columns were added by an adding machine and their means determined. In the 
case of a considerable number of such sets the standard deviations were also found, 
in order that the probable error of the means might be determined. 
The type contour was now found by plotting the mean vertical axis, the mean 
nasion-gamma line or the mean glabella-occipital line as the case might be. This 
was divided into ten equal parts by the proportional compasses, and the perpendicular 
lines, as well as the terminal quarter lines drawn. Along these were plotted right 
and left the mean lengths, and in the case of the sagittal section the mean glabella 
tangent and its mean point of contact. From these points by aid of a spline the 
three type sections of each series of crania were determined. These form the 
cranial types of Dr Crewdson Benington's investigation. Upon them the mean 
position of bregma, lambda, inion, basion, etc., the auricular point and other cranial 
mean characters, calvarial height and the Schwalbe angles, can be introduced, these 
positions being determined from their mean coordinates*. 
* We have found close agreement, whether these points be put in by mean coordinates or inserted 
on the contour by mean distances from nasion, or, where necessary (e.g. auricular and alveolar points), 
by mean distances from two points (e.g. nasion and gamma). 
