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De. Cunningham—Surface Anatomy of the Primate Cerebrum. 163

In those cases in which the upper extremity of the fissure does not reach
the superior margin of the cerebral hemisphere, as well as in those cases in
which it fairly turns over to reach the inner surface, the sulcus usually ends
by bending directly backwards for a distance of about a quarter of an inch
or more. On the inner surface of the hemisphere it approaches the upwardly
directed end of the calloso-marginal sulcus, but I have never seen it join
the latter. Benedikt * describes such a union. He says : "In several brains
the fissure of Rolando, which in these cases projects far upon the mesial
surface, also stands in connexion with the fissura calloso-marginalis."
Eberstaller doubts the existence of this connexion. In the large number
of brains which he has examined, he has never met with an example.

Where the upper extremity of the fissure of Rolando just reaches the
upper border of the hemisphere, but fails to turn round it, we do not as a
rule see the terminal backward bend which is so characteristic of the two
other forms of ending.

Eberstaller believes that the upper end of the fissure of Rolando almost
invariably turns over the upper border of the hemisphere. He says:—
" Die Centralspalte uberschreitet fast immer die Mantelkante, und endet
erst auf der Innenflache der Hemisphere ; zum mindesten wird die Mantelkante
erreicht, und ist somit das Furchenende bei der Betrachtung der
Medianflache wahrnehmbar; dass die Mantelkante nicht erreicht wird,
ist eine seltene Ausnahme."

In the great majority of cases the lower end of the Rolandic fissure
falls short of the fissure of Sylvius. In 19 per cent, of the same fifty-two
hemispheres to which I have already referred, and which comprised a
nearly equal number of male and female brains, a shallow connexion was
established. The cases in which this was observed may be classified as
follows :—

(3 times on the right side. 4 times in the female.

4 times on the left side. 6 times in the adult.

6 times in the male. 4 times in children.

I may further state that although I examined twenty-one hemispheres
of the new-born child, the connexion was only present in one instance.

* Anatornische Studien an Yerbrecher-Gehirneu. Wien, 1878.

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