Freiburger historische Bestände – digital

232

Cunningham Memoirs.

the presence of a deep annectant gyrus which is occasionally seen crossing
the bottom of the ramus occipitalis at its junction with the sulcus transversa
occipitalis. In twenty-eight adult hemispheres I have seen this deep

Fig. 51.

-The two cerebral hemispheres of a foetus (seven and a-half months) viewed from above. The
figure is reproduced from a photograph. The left hemisphere is remarkable on account
of the number of separate depressions which together represent the postcentral sulcus.

Fissure of Rolando.
Sulcus postcentralis inferior.
Sulcus postcentralis superior.
Ramus horizontalis.

s.t.
p.o.

Ramus occipitalis.

Sulcus occipitalis transversus of Eclcer.
Parieto-occipital fissure.

gyrus in three specimens; in the full-time foetal brain, however, I have met
with it more frequently.*

* It appears to me that the sulcus occipitalis transversus presents very much the same relations
to the ramus occipitalis that the fronto-marginal sulcus of Wernicke exhibits to the sulcus frontalis
medius. Both of these transverse furrows form the terminal bifurcations of the sagittal
6ulci with which they stand in connexion; and further, as we shall see later on, the fronto-
marginal furrow may be developed in three ways, which correspond exactly with the three
modes of development described for the sulcus transversus occipitalis : (1) as an independent
furrow; (2) its mesial limb may be developed separately, whilst its lateral limb is developed in
direct continuity with the sulcus frontalis medius ; (3) the lateral limb may show an independent
development, whilst its mesial limb is formed in direct continuity with the sulcus frontalis medius.