CHAP. XXL] OF THE 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 Bush woman'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 margins are not very closely adapted 



FIG. 136. The Brain of a Irishwoman, lateral aspect. (Heath, after Marshall.) 

 Letters and figures of reference in part as in last figure. 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 portion of the island of Keilor 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 highly developed 

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

 direction. 



