Chap. XXL] OF THE HUMAN BRAIN. 895 



in the shortness of the Sylvian Fissure. It may 

 scarcely reach half way back to the upper end of the 



* perpendicular fissure,' and may be separated therefrom 

 by several convolutions instead of only by the descending 

 limb of the ' angular gyrus,' as is the case in the Chim- 

 panzee ; or by this convolution together with the upper 



* bridging convolution,' as in the two South African 

 women. 



The Sylvian Fissure is most elongated in some of the Quadru- 

 mana such as the Howler (p. 291), and also in the brains of the 

 Saimiri depicted by Gratiolet,* in each of which it extends back 

 almost to the ' great longitudinal fissure.' It is only slightly less 

 elongated in the Squirrel Monkey, the Macaque and other allied 

 forms (figs. 105, 106) ; and is similarly long even in the Chimpan- 

 zee.f It has been already pointed out (p. 345) that the length of 

 the Temporal Lobe, and the extent of the posterior prolongation 

 of the fissure of Sylvius, are also notable characteristics of the 

 human foetal brain. This feature is well shown in Gratiolet's figure 

 of the brain of a foetus of about 6^ months. J 



This Simian and foetal characteristic of the organ reveals itself 

 also even in the adult condition of some of the lower types of the 

 Human Brain. It is seen, for instance, in the Hottentot Venus (fig. 

 133) and to a less extent in the Bushwoman (fig. 136) ; also in the 

 brain of the criminal Fieschi (of ' infernal machine ' notoriety) 

 as depicted by Gratiolet,§ and in that of the artizanKrebs as repre- 

 sented by Wagner. II In Leuret and Gratiolet's figure of the brain of 

 a ' Charruas ' (PI- xix. fig. 1), however, though it presents in other 

 respects many infantile characters, we find the fissure of Sylvius 

 very short, just as it exists in some of the best developed human 

 brains, e.g. that of Gauss, and still more notably in that of De 

 Morgan, as well as in the Journalist above referred to. In both of 

 these latter brains more than one-half of the Sylvian Fissure, aa 

 it exists in some of the Qaadrumana, has bean obliterated — since 



* " Anat. Comp. du Syst. Nerv.," PI. xxix. figs. 11 and 12. 



f Gratiolet, loc. cit. PI. xxiv. fig. 6. 



+ Idem. PI. XXX. fig. 2. 



§ PI. xxij. fig. 2. 



II " Yorstudien," tab. vi. fig. 2. 



