Freiburger historische Bestände - digital

222

Cunningham Memoirs.

length of the descending limb of the intraparietal sulcus lies exposed on
the surface of the cerebrum in front of the opercular lip.

In dealing with this region of the simian brain I have avoided using the
term " external parieto-occipital fissure,"^ because it has been employed in
this country in so many different senses. Thus it has been used to denote :

Fia. 45.—Cerebrum of Cebus capucinus viewed from above. Drawn by tbe American apparatus for
tracing orthogonal projections of tbe skull. Tbe binder end of the cerebrum is tilted
upwards, in order that the occipital part may be brought more fully into view. On the
left side the occipital operculum has been removed, so that tbe descending binder part
of tbe intraparietal sulcus may be displayed. The cut surface of the operculum
is represented by shading. On the right side the operculum is in place, and the bottom
of the " Affenspalte " and the hinder end of the intraparietal sulcus, under cover of it,
are represented by dotted lines.

/. . . Sulcus frontalis inferior.

p.c. . . Sulcus prsecentralis inferior,

r. . . Fissure of Eolando.

s. . . Fissure of Sylvius.

p. . . Intraparietal sulcus.

p.o. . . Parieto-occipital fissure.

o. . . Anterior lip of the occipital operculum.

a.f. . . Bottom of the " Affenspalte."

(1) the incision which is made in the upper margin of the hemisphere
by the internal parieto-occipital fissure, and this is the only sense in which
it should be used; (2) the superficial furrow which, when the operculum is
in position, runs along the anterior lip of this structure, and at first sight
appears to be continuous with the true parieto-occipital fissure on the
inner surface of the hemisphere; and (3) the bottom of the pocket or recess
enclosed by the operculum. Owing to the different degrees of development