Freiburger historische Bestände - digital

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Cunningham Memoirs.

13. Both of these furrows have secured a firm footing in the human
brain, but one only (viz. the sulcus frontalis medius) has established itself
upon the brain of the chimpanzee.

14. The sulcus frontalis medius assumes a definite form, and runs in a
sagittal direction in the anterior two-thirds of the middle frontal gyrus.
In front it is connected with the fronto-marginal sulcus of Wernicke ;
behind there are usually two transverse furrows, which are sometimes
connected not only with the sulcus frontalis medius, but perhaps also with
the ramus horizontalis of the inferior prsecentral furrow.

15. The sulcus frontalis mesialis consists of several irregular furrows
which follow each other in series midway between the sulcus frontalis
superior and the mesial border.

16. Sometimes these are joined so as to constitute a continuous furrow
which completely divides the superior frontal convolutions into two parts.

17. The sulcus frontalis mesialis is absent or poorly developed in the
brain of the negro.

18. When all the frontal sulci are well developed, there are five more
or less distinct tiers of sagittal convolutions in the frontal lobe.

19. The frontal furrows may be placed in order, according to their
morphological importance, as follows: (a) sulcus prsecentralis inferior;
(b) sulcus frontalis inferior; (c) sulcus prsecentralis superior and basal part
of the superior frontal sulcus; (d) remaining parts of the superior frontal
sulcus ; (e) sulcus frontalis medius ; (/) sulcus frontalis mesialis.

20. The sulcus prsecentralis inferior and the inferior frontal sulcus are
the furrows which are most firmly impressed on the brain of the apes. In
Cebus they alone are present; in Callithrix there are also traces of the sulcus
prsecentralis superior and sulcus fronto-orbitalis ; in the baboon there are,
in addition, a rudimentary sulcus frontalis superior, and perhaps (?) traces
of a sulcus frontalis medius.

21. In the chimpanzee and the gorilla the sulcus frontalis medius is
often present in a form precisely similar to that seen in the human brain;
in the orang the condition of this sulcus is doubtful; in the gibbon the
sulcus frontalis medius is absent.

22. In the chimpanzee, therefore, the same convolution tiers may be