396 THE EXTERNAL CONFIGURATION 



the measurements of these brains from the upper end of the 

 ' perpendicular Fissure ' across the parietal lobe to the posterior 

 extremity of the Sylvian Fissure, are just equal to the measure- 

 ments from the latter point even as far as the tip of the correspond- 

 ing Temporal Lobe. 



This progressive shortening of the Sylvian Fissure appears not 

 to have been distinctly pointed out before. Yet it would seem 

 to be a change of precisely the same order as that which leads to 

 the progressive obliteration of the ' external perpendicular Fis- 

 sure,' to which much attention has been given by anatomists. 



The above-mentioned shortness of the Sylvian Fissure 

 in the more highly evolved brains tends to confer a 

 corresponding shortness upon the Temporal Lobe. The 

 proportional breadth of this segment of the brain is also 

 decidedly diminished in the brain of Gauss. The broad 

 simple convolutions of the Temporal Lobe in the Hotten- 

 tot Venus (fig. 133) contrast notably with the much more 

 complex corresponding gyri in the brains of the two 

 Mathematicians as well as in that of the Journalist.* 



The Occipital Lobe has a much greater depth in the 

 brains of Gauss, De Morgan and of the Journalist, than 

 is to be met with in the lower human types previously 

 described. Consequently in them the inferior-posterior 

 border of the Cerebral Hemisphere, as it extends along 

 the side of the Cerebellum, is much more nearly horizon- 

 tal than it is in either of the two African women. In 

 these latter, however, an advance of the same kind is to 

 be met with in comparison with what obtains in the Cere- 

 bral Hemispheres of the great ' man-like ' Apes (p. 296). 



* In the brain of the 6| month Foetus, and in that of Fieschi 

 represented by Gratiolet (loc. cit., PL xxx. fig. 2, and PL xij. fig. 2) 

 the Temporal Lobes are both long and broad, whilst in that of the 

 new-born Infant (PL xxx. fig. 3), and in the brain of the ' Charruas ' 

 (PL xix. fig. 1), this same Lobe though short ie still extremely 

 broad. 



