164 THE ROYAL SOCIETY OF CANADA 



For instance Berry and Robertson^ found that it reached a minimum 

 of forty-nine in a series of one hundred of these. The angle in a 

 Melanesian skull investigated by the writer^ was- ascertained" to be 

 fifty-five which represents an evolutionary advance of only 9% above 

 the Piltdown type. The angle in a modern European cranium taken 

 at random from the writer's collection was found to be sixty-two 

 which represents evolutionary progress to the extent of 19-4% above 

 the Piltdown type. This certainly is a very substantial gain, and is 

 another indication of the decided evolutionary activity that has been 

 shown to be taking place towards the frontal end of the cranium, not 

 only upwards and forwards, but also in a transverse direction as 

 previously discussed in Section I. Fig. 7 has been designed to show 

 the relative extent of the bregmatic angle in the Java skull (B"), the 

 Piltdown skull (B'), and a modern European type of skull (B")- 

 This figure demonstrates the gradual swinging upwards and forwards 

 of the line BG, opening up as it were like a lid, with the glabella as the 

 position of the hinge. It will be noted from the figure what a relatively 

 large addition to the cranial capacity is secured by even a very slight 

 degree of swing movement. One is thereby enabled to appreciate how 

 valuable is the index of cranial superiority furnished by a study of the 

 bregmatic angle. 



The expansion of the frontal cranial arc is the striking feature of 

 the skull of white races, therefore the higher up the scale one goes, 

 one finds a gradual increase in the maximum distance between the arc 

 and the glabella-bregma chord, which I found to be about 25 mm. as 

 the average of twelve Canadian crania. A study of Fig. 7 thus shows 

 that there are two great factors in operation during the evolution of 

 the frontal region of the skull. The first is a gradual increase in the 

 size of the bregmatic angle, while the second is superadded to this in 

 the form of a concomitant bulging outwards and forwards of the 

 frontal cranial arc, rather after the fashion of the way in which an 

 archer bends his strongbow. It is necessary to pay attention first of 

 all to the glabella-bregma chord which, to carry the previous analogy 

 further, might be termed the string of the bow. I calculated this to 

 be 9-4 cm. long in Dubois' reconstruction of the Java skull, whereas 

 it proved to have an average length of about 11 cm. in the modern 

 Canadian cranium. This represents an increase of 14-5%, and its 

 vast effect in increasing the capacity of the frontal end of the skull 

 can be best appreciated by studying Fig. 7, where it will be observed 

 to add the strip of territory between the two curved dotted lines to 

 the cranial capacity — a very substantial addition indeed, it may be 



' op. cit. 



2 Trans, and Proc. of the Nova Scotia Institute of Science, 1917-18. 



