Freiburger historische Bestände - digital

De. Cunningham—Surface Anatomy of the Primate Cerebrum. Ill

these authors describe in the chimpanzee and orang an occasional ascending
limb of the fissure of Sylvius. Herv^ states that he has seen this additional
limb once in five chimpanzee brains, and twice in a similar number of brains
from the orang, and he goes on to affirm that when it exists, " il en requite
la formation, entre elle etla branche horizontale anterieure, d'un cap plus ou
moins arrondi, et alors, au premier abord, F3 (i. e. the inferior frontal convolution
) semble ddcrire sur ces deux branches un double meundre." He
further observes, that this supposed ascending limb cuts the operculum
behind the prsecentral sulcus, and is therefore a fissure in the basal part of
the ascending frontal convolution. We refuse to consider a fissure in such
a position as presenting anything in common with the ascending limb of
the Sylvian fissure in man. Much more likely is it the representative in the
anthropoid ape of the sulcus transversus inferior of Eberstaller, the intermediate
link between the sulcus centralis insula? and the fissure of Rolando.

But there are other and more cogent facts which may be urged against
the view advanced by Broca and Herve\ If we are to regard the anterior
limb of the Sylvian fissure which bounds the fronto-parietal operculum in
front in the anthropoid brain as homologous with anything, it must be with
the ascending limb of the human brain, and for this reason : the part of the
island of Reil which corresponds to the frontal operculum or pars triangularis in
man is absent in the chimpanzee. In other words, there is no submerged
gyrus brevis primus insula? in the chimpanzee brain.

I restrict the term " insula " in this case to the part of the brain-surface
which is covered by the two opercula—parietofrontal and temporal. It
may be necessary at a future time to discuss whether or not a portion of
the insula, as it exists in man, is not on the surface of the hemisphere of
the anthropoid ape, and fully exposed to view. In other words, we may
require to decide whether a portion of the so-called inferior frontal convolution
in the anthropoid is not in reality the equivalent in the ape of
the front part of the island of Reil in man. If this be the case, the
sulcus anterior Reillii in man is the sulcus fronto-orbitalis in the
anthropoid.

This leads us to speak of the gyri and sulci on the surface of the island
of Reil in the anthropoid brain. These are very poorly developed, and