Freiburger historische Bestände - digital

234

Cunningham Memoirs.

hundred hemispheres, but have never recognised such a projection of its
posterior border; quite the opposite: in most cases it is the anterior
border which shows an operculum-like projection; therefore the whole
hinder half of the interparietal furrow penetrates the cerebral surface
obliquely, so that the hinder part of the inferior parietal lobule overlaps
the hinder part of the upper parietal lobule and the fore-border of the occipital
lobe. Stark makes an analogous observation, and this agrees entirely
with the higher development of the human brain. The parietal and occipital
lobes contend with each other for surface-extension; in the lower
apes the latter bulges over the former: it remains the victor and reaches
forwards as far as the first annectant gyrus. Already in the orang-utan the
occipital operculum has suffered a great reduction; but in man the victory
is on the side of the parietal lobe ; it presses the other (the occipital lobe)
back and begins on its part to overlap it." I fully agree with these suggestive
remarks of Eberstaller, and can corroborate his statements regarding
the preponderance of the inferior parietal lobule in the cerebrum of man.

It is hardly necessary to allude to the views which have been put
forward by Wernicke* in regard to the " Affenspalte." He describes a
transversely directed furrow on the outer surface of the human brain, and
in a line with the parieto-occipital fissure. This he terms the " vordere
Occipitalfurche," and he holds that it is the representative of the " Affenspalte
" in the apes. Eberstaller has conclusively shown that the furrow in
question is merely the vertical terminal bifurcation of the second temporal
furrow. It stands in relation to this furrow in the same manner as the
corresponding terminal bifurcations do to the parallel and Sylvian fissures,
and also, we might add, as the sulcus transversus occipitalis of Ecker does
to the ramus occipitalis of the intraparietal sulcus.

VIII. Deep Annectant Gyri in the Intraparietal Sulcus.—Eberstaller
has given so satisfactory a description of the deep gyri which bridge across
the bottom of the intraparietal sulcus in the adult human brain that it is
not necessary to enter into this aspect of the question in any detail. In the

* " Das Urwindungssystem des menschlichen Gehirns.—Archiv fur Psychiatrie und Nerven-
krankheiten," Band vi., Heft i., 1875.