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parietal into a supero- and infero-anterior and supero- and infero- 
posterior parietal regions, and marks off also an in fero- frontal area 
on the frontal bone. The frontal bone may be still further sub- 
divided into a supero-and mid-frontal region by a longitudinal line 
drawn back from the upper border of the orbit through the frontal 
eminence to the coronal suture. 
With a fine saw I then cut out, one after another, the pieces of bone 
along the lines which constituted the boundaries of these different 
regions, and examined with care the particular convolution, or group 
of convolutions, which lay immediately subjacent to the portion of 
bone removed. In this manner I was able to localise in the speci- 
mens examined the relations of the convolutions to the surface of 
the skull and head. As I have already detailed the results of my 
examinations in the “ Journal of Anatomy and Physiology,” Novem- 
ber 1873, 1 need not repeat them here; but it may not be out of place 
to point out that the lobes of the brain by no means precisely corres- 
pond to the areas of the cranial bones, after which four of them are 
named. The frontal lobe is not only covered over by the frontal 
bone, but extends backwards for a considerable distance under cover 
of the parietal bone. If we accept, as I have elsewhere described,* 
the fissure of Eolando as the posterior limit of this lobe, then the 
larger part of the antero-parietal region corresponds with the 
frontal lobe, for not only does it contain the origins of the superior, 
middle, and inferior frontal gyri, but also the ascending frontal 
convolution. But even if we were to regard the ascending frontal 
gyrus, and not the fissure of Rolando, as bounding the frontal lobe 
posteriorly, the frontal lobe would still not be wholly localised 
under cover of the frontal bone, for the superior, middle and 
inferior frontal gyri all arise from the ascending frontal gyrus, 
behind the line of the coronal suture. 
The occipital lobe also is not limited to the region covered 
by the squamous part of the occipital bone, but slightly over- 
lapping the lambdoidal suture, extends forwards for a short dis- 
tance into the back part of the upper postero-parietal area, and 
through the superior annectent gyrus reaches the parieto-occipital 
fissure. 
* Edinburgh Medical Journal, June 1866, and separate publication, “The 
Convolutions of the Human Cerebrum topographically considered.” 
