Chap. XXL] OF THP: HUMAN BRAIN. 381 



compared with that of the European, was found to be 

 specially defective in depth and vertical height. 



Fissures, Lobes, and Convolutions of the Cere- 

 brum. '' The fissure of Sylvius in the Bushwoman's 

 brain extends well backwards, but inclines more upwards 

 than in the European brain,* and its course is marked 

 soon after its commencement by a peculiar horizontal 

 step Its mar/T^ins are not very closely adapted 



Fig. 136.— The Brain of a Biishwoman, lateral aspect. (Heath, after Marshall) 

 Letters and figures of reference in part as in last figiue. T, temporal lobe ; c. island of 

 Reil ; e, e, fissure of Sylvius ; 1, 1, lower or third fronlal convolution ; 7, 7 ; 8, 8 ; 9, 9, 

 three temporal convolutions ; /, /, and g, g, parallel, and inferior temporal fissures. 



together, especially opposite the hinder border of the 

 frontal lobe, which is here very defective. The fissure, 

 indeed, is so patent, that without any separation of its 

 margins, a jDortion of the island of Reil or central lobe (C), 

 though small, is distinctly visible. This condition recalls 

 to mind the foetal state of the human cerebrum (fig. 128), 



* These are marks of low development. In more liigldy developed 

 brains the Sylvian fissure is shorter as well as more horizontal in 

 direction. 



