( 366 ) 
The base line of my system, to which all further ratios will be 
referred, and with respect to which the values of angles will be 
determined, is indicated in Fig. 1 in the mediagram of a Cebus 
skull. As frontal point I chose the lowest point of the frontal 
wall of the skull where the interior surface of the skull bends 
inwardly in a more or less sharp curve to be continued in the roof 
of the nasal cavity. The determination of this point presents no 
difficulties, as a rule,, since in the median plane the interior surface 
of all Primate skulls possesses a distinct frontal wall which may be 
more or less inclined and may pass more or less gradually into the 
cranial roof, but which is still always present. I might express this 
fact as follows: in the median section all Primate skulls possess 
internally a front. On both sides of the median plane this frontal 
wall disappears, since the roof of the orbitae approaches very closely 
under the cranial roof, so that the cranial plane and the orbital roof 
join’ under an often very acute angle. It will be shown in a following 
communication that the human front has its origin not exclusively in 
a higher vaulting of the frontal bone but also to no small extent in 
a downward displacement of the eye-sockets. Also in Aeby’s work 
I find this idea already expressed and it seems to me that the inves¬ 
tigations of recent years on this part of the skull would have taken 
a different course if more attention had been paid to the facts in 
Aeby’s work. 
The transition of the cerebral into the nasal plane, i. e. in general 
the foremost lowest point of the anterior surface of the skull, can in 
most cases be determined at once. Only in a few cases I met with 
some difficulty in this respect, namely with the skulls of Javanese, 
since here I found, except in a single case, a frontal crist projecting 
very far into the cranial space. For the sake of brevity I shall 
henceforth call this anterior point of the base line the “Fronton’. 
The second point I determined by means of compasses from the 
first. I namely sought on the posterior wall the point which is at 
line. Now 1 have measured in the mediagrams of my adult human skulls the angles 
which the Basion-Bregma line forms with the line of Klaatsch and with that of 
Schwalbe and found the following results. In 70 human skulls the angle which 
the Basion-Bregma line forms with the glabella-lambda line (Klaatsch), varies 
between 84 and 98 degrees and the angle which this same line forms with the 
glabella-inion line (Schwalbe) between 104 and 117 degrees. According to the 
method of Klaatsch the top of the variation curve lies at 90° (in 17 out of 70 
cases), according to the method of Schwalbe at 112° (in 14 out of 70 cases). 
Irom this comparison it is obvious that the proper displacement of the inion is 
no larger than that of the lambda and that consequently on this account neither 
of the two l-nes is to be preferred to the other. 
