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Cunningham Memoirs.

junction was effected by a knuckling down of the ascending parietal convolution
. When such connexions occur it appears to be common for the
ascending frontal convolution to be divided in one or more places as well.

It is interesting to note that in a cerebral hemisphere obtained from
a chacma baboon a superficial connexion was also observed between the
ramus postcentralis superior and the fissure of Rolando.

V. The Ramus Occipitalis of the Intraparietal Sulcus.—This is
unquestionably the most interesting part of the intraparietal system of
furrows, and in the human brain its exact homology with the condition
present in the apes is somewhat difficult to ascertain. In man it describes a
U-shaped curve around the first annectant gyrus, and limits it externally.
In front it is, as a rule, connected with the ramus horizontalis, whilst behind
it ends in a short vertical furrow to which Ecker has applied the name
of sulcus occipitalis transversus. A careful description of its course and
relations is given by Schwalbe,* Ecker,"j* Gegenbaur,J Pansch,§ Eber-
staller, || and other authors. The transverse occipital furrow is a shallow
sulcus which runs transversely across a small extent of the outer surface of
the occipital lobe a short distance behind the parieto-occipital fissure as it
appears upon the superior border of the hemisphere. It is generally
regarded as the representative of the " Affenspalte" in the apes, and therefore
as a distinct and separate fissural integer. This conception of the
sulcus transversus requires considerable modification.

The extremely concise description of Eberstaller may be regarded as
embodying the general views which are held on this subject. He says:—
" We proceed now to the consideration of the interparietal sulcus. This
' Furchen conglomerat' is disposed in three typical parts : an anterior
transverse portion (sulcus postcentralis), a posterior transverse piece (sulcus
transversus of Ecker), and a sagittal piece—the sulcus interparietalis in the

* Lehrbuch der JSTeurologie. Erlangen, 1881.

f Entwicklungsgeschichte der Furchen und Windungen, &c, &c, already referred to ; and
also his book, entitled Die Hirnwindungen des Menschen. Braunschweig, 1883.

% Lehrbuch der Anatomie des Menschen, Band 11. Vierte Auflage. Leipzig, 1890.

§ Die Furchen und Wiilste. Berlin, 1879.

U Wiener Medizinische Blatter, 1884, No. 18, p. 547.