512 
PROFESSOR MARSHALL ON THE BRAIN OP A BUSH WOMAN ; AND 
pean brain, however, this fissure joins the fissure of the hippocampi below (Plate XIX. 
fig. 5), whilst in the Quadrumana it usually stops short of that fissure, owing to the 
development of a superficial connecting convolution in that situation. 
The fissure of the hippocampi (Plates XVIII. & XIX. figs. 4 & 5, l-l, m) is nearly 
horizontal. Its outer or calcarine portion (l-l) ends in two shallow sulci, or notches, on 
the tip of the posterior lobe; it extends a little further forwards than is customary 
beneath the corpus callosum, but is separated, as usual, from the inner or dentate portion 
(m) of the fissure by a ridge of cerebral substance (#=), which connects the convolution 
of the corpus callosum (is) with the uncinate convolution (19). The dentate fissure (m) 
is shallow. The inferior middle temporal , parallel or collateral fissure (Plate XIX- 
fig. 5, n-n) is very long and simple, and may be traced further upwards on to the 
hinder surface of the occipital lobe than usual. 
On the whole, the fissures of the left hemisphere are rather more complex than those 
of the right, which would seem to be not only smaller but inferior in organization. 
This want of symmetry is itself, however, a mark of comparative elevation. 
With a few exceptions, these primary fissures are somewhat more complex than those 
represented in Gratiolet’s figures of the brain of the Hottentot Venus ; but neverthe- 
less they are far more simple and more easily distinguished amongst the numerous 
secondary sulci than in the ordinary European brain. In this greater simplicity and 
definition of the fissures generally, in the slightly more vertical direction and step-like 
course of the Sylvian fissure, and in the decidedly more upright position of the internal 
perpendicular fissure, the Bushwoman’s brain approaches somewhat the quadrumanous 
characters; but it deviates more widely from them by the special interruption of the 
external perpendicular fissure, by the greater length and inclination backwards of the 
fissure of Rolando, by the more marked want of symmetry on the two sides of the 
brain, and by the greater number and complexity of the secondary sulci. 
The lobes. — Regarding the more important fissures as the true lines of subdivision 
between the cerebral lobes, we find that the frontal lobes (F), though contracted in 
width and depth, are proportionally long, that the parietal lobes (P), though high, are 
relatively contracted from before backwards, especially behind, that the occipital lobes 
(O) are very shallow from above downwards, and very pointed, that the temporal lobes 
(T) are long and narrow, and that the island of Reil, or central lobe (C), is small and 
partly visible at the entrance of the Sylvian fissure. 
The convolutions and secondary sulci. — The orbital sulci and convolutions of the frontal 
lobe (Plate XVII. fig. 2) are certainly remarkably simple. The olfactory sulcus, which 
lodges the so-called olfactory nerve ( 0 ), has its ordinary length ; but, owing to the short- 
ness of the frontal lobe, it reaches to within half an inch of the tip of that lobe, whilst 
in the European it does not reach within one inch of that point. On the inner side 
of this sulcus is seen, as usual, the edge of the great marginal convolution (17) of the 
inner surface. To its outer side, the deep triradiate sulcus, which cuts up the rest of 
the orbital surface into a posterior convolution (hi) limiting the Sylvian fissure, an 
