468 EVOLUTIONARY MORPHOLOGY 



coincidence up to the top of the skull, and drawing a line at 

 right angles to it through Sollas' centre. 



One of the most instructive readings is the measurement 

 of the angle made between the line of the foramen magnum, 

 and the line from the centre to the point of junction between 

 the nasal and frontal bones (the nasion). It is essential for 

 this comparison that the sections be taken from specimens of 

 equivalent age, for during development the angle changes. 

 Nevertheless, taking adult material it is possible to make out 

 the following : — 



Angle between foramen magnum and nasion in adult : 



These measurements show that the periphery of the brain- 

 case in modern man amounts to three right angles, and it is 

 interesting to note in comparison with lower forms that the 

 accommodation for the increased size of man's brain is obtained 

 by the angular increase in the periphery of the brain-case as 

 well as absolute increase in size. 



It is also noticeable that Eoanthropus approaches nearer to 

 sapiens than do neanderthalensis and rhodesiensis, which is an 

 additional reason for including the former but excluding the 

 latter from sapiens' ancestry. 



As regards Australopithecus, the following table shows the 

 comparison between it and juvenile specimens of other forms. 



Angle between foramen magnum and nasion in young : — 



Orang 243 



Chimpanzee . . . . . . . . . . . . . . 252 



Australopithecus . . . . . . . . . . . . 258 



Homo sapiens child . . . . . . . . . . . . 282 



It is clear, therefore, that the Taungs skull approaches the human 

 condition in this respect, though still remaining similar to the 

 Chimpanzee. 



Having now reviewed the material on which all study of 



