ON THE BRAINS OF TWO IDIOTS OF EUROPEAN DESCENT. 
511 
considerably beyond the middle of the long axis of the cerebrum, nearly as far back as 
the line of greatest width of that organ ; so that it passes proportionally further back than 
in the Hottentot Venus, or indeed than in the European, as illustrated in the outlines 
of the three brains given in Plate XX. figs. 7, 8, & 9. The left fissure reaches a little 
further back than the right. 
The external perpendicular fissures (Plates XVII. & XX. figs. 1 & 9, h, h ) can be 
traced as easily as in the Hottentot Venus (Plate XX. fig. 8), but are soon interrupted 
by the external connecting convolutions (a, /3). Towards the sides, these fissures are cer- 
tainly more easily followed than in the European — a circumstance which imparts a 
lower character to this part of the Bosjes brain ; at the same time they are far more 
interrupted than in the Chimpanzee or Orang-outang (Plate XXIII. fig. 20). These 
short external perpendicular fissures join, as usual, the summits of the internal perpen- 
dicular fissures (Plate XVIII. fig. 4, k), and, together with the fissures of Rolando, 
divide the upper surface of the cerebrum into three regions. Supposing the total 
length of the hemispheres, as seen vertically, to be represented by 100, the region in 
front of the point of the V formed by the two fissures of Rolando is equal to 65 ; 
thence to the perpendicular fissures equals 17 '5; and thence to the tips of the poste- 
rior lobes, also 17 - 5. The proportions in the European are 57, 23, and 20 ; in the Chim- 
panzee, 49, 28, and 23. Measured longitudinally over the vertex, the relative spaces 
occupied by these regions are, in the Bushwoman, as 60, 15, and 25 ; in the European, 
as 54, 23, and 23; in the Chimpanzee, as 46, 28, and 26. So that the fronto-parietal 
region in the Bushwoman appears lengthened backwards, with a proportionate want of 
development in the purely parietal and occipital regions. 
The remarkable irregular and very deep fissure (Plate XVIII. fig. 3, c-c) always seen 
on the outer side of the frontal lobe ( antero-parietal , Huxley) is very strongly marked. 
It commences about one inch behind the entrance of the fissure of Sylvius, with which 
it is more nearly continuous than in the European brain, except in the foetal condition; 
passes more obliquely backwards than usual ; and corresponds with the place of deficient 
width in this region already twice alluded to. 
The parallel fissure (f-f) on the side of the temporal lobe is more tortuous on the 
left side than in the Hottentot Venus, though less so than in ordinary European brains. 
The inferior temporal fissure (g—g) is comparatively short and simple. 
On the internal surface of the hemisphere, the great fissure of the fronto-parietal lobe 
(Plate XVIII. fig. 4, i-i), or calloso-marginal fissure , is twice interrupted by convolu- 
tional bridges, once (as usual) in front of the corpus callosum, and once (unusually) 
above the middle of that body. As in ordinary European brains, it reaches the surface 
of the hemisphere, well behind the hinder border of the corpus callosum. 
The internal perpendicular fissure (Plates XVIII. & XIX. figs. 4 & 5, k-k) is more 
vertical than in the European, but much less so than in the Chimpanzee — the angle 
formed by this fissure and a base-line drawn through the corpus callosum being in the 
European 123°, in the Bushwoman 115°, and in the Chimpanzee 93°. As in the Euro- 
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