Freiburger historische Bestände - digital

Dr. Cunningham—Surface Anatomy of the Primate Cerebrum. 295

it is carried forwards above the upper end of the sulcus fronto-orbitalis.
At a higher level is seen the sulcus frontalis medius; and it will be
observed that this ends at the superciliary margin in a well-marked sulcus
fronto-marginalis of Wernicke.

Eberstaller's drawings of the chimpanzee cerebrum are not very distinct,
but it appears to me that in the left hemisphere which he has figured
(Das Stirnhirn ; p. 116, fig. 7), the long furrow proceeding forwards from
the upper part of the vertical stem of the inferior prsecentral sulcus is
the representative of the sulcus frontalis medius. I am confirmed in
this opinion by his remark that it "is traversed by deep bridging
gyri."

The arrangement of the frontal furrows of the orang is extremely
puzzling. It is true that in the case of the hemisphere represented in
figure 70. I attempt the interpretation of the various conditions exhibited,
but I am not at all satisfied that I am even approximately correct.
The only furrows which can be recognized beyond doubt are the
sulcus fronto-orbitalis, the sulcus prsecentralis superior (of which the
upper part alone is present), and the two separate parts of the sulcus
frontalis superior. I have marked a furrow fm., thereby indicating
the possibility of its being the sulcus frontalis medius, but I fully recognize
that there is very nearly as much likelihood of its being a third part of
the sulcus frontalis superior.

To judge from the beautiful figures which are given by Waldeyer* f
and the two very clear and distinct diagrams of KohlbrliggeJ there
seems to be an absence of the ramus horizontalis of the inferior prsecentral
sulcus and also of the sulcus frontalis medius in the gibbon. The
sulcus frontalis inferior is strongly marked, and stands in connexion
with the vertical stem of the inferior prsecentral furrow.

* " Sylriscbe Eurcbe und Keil'scbe Insel des Genus Hylobates," Sitzungsbericbte der
Kbniglicb Preussiscben Akademie der Wissenscbaften zu Berlin, xvn., 1891.

f "Das Gibbon-Hirn," Internationale Beitrage zur "Wissenscbaftlicben Hedicin. Vircbow's
Festscbrift. Band i.

X " Versucb einer Anatornie des Genus Hylobates," Zoologische Ergebnisse einer Beise in
Medcrliindiscb Ost-Indien berausgegeben von Dr. Max AVeber. Band n., p. 189, figs. a. and b.
Leiden, 1891.