ON THE BEAINS OF TWO IDIOTS OF EUROPEAN DESCENT. 
557 
PLATE XXIII. 
Fig. 18. Convolutions of the upper surface of the brain of the female idiot. 
Eig. 19. Convolutions of the upper surface of the brain of the male idiot. 
N.B. In both of these figures a few additional markings, not represented 
in figures 10 and 14, have been put in from careful examinations of 
the brains themselves. 
Fig. 20. Convolutions of the upper surface of the brain of an Orang-outang (after 
Gratiolet’s restored figure). 
Fig. 21. Outer surface of the left hemisphere of the cerebrum of a human foetus, at 
probably between the fourth and the fifth month. 
Fig. 22. Median vertical section of the same foetal cerebrum, showing the inner surface 
of the same hemisphere. 
Fig. 23. Vertical median section of the medulla oblongata and pons Varolii of a pre- 
served European brain, to show the area (p) occupied by the divided trans- 
verse fibres of the pons. 
Fig. 24. The same parts from the brain of the Bush woman. 
Fig. 25. The same parts from the brain of the female idiot. 
Fig. 26. The same parts from the brain of the male idiot. 
References to the Lobes, Fissures, and Convolutions. 
The names here given to the fissures and convolutions are, for the most part, founded 
on M. Gratiolet’s nomenclature. 
Ce. The cerebellum. 
Lobes. 
C. Median lobe, or Island of Reil. 
F. Frontal. 
P. Parietal. 
O. Occipital. 
T. Temporal. 
Fissures. 
c-c. Antero-parietal (Huxley). 
d-d. Rolando’s. 
e-e. Sylvian. 
/-/. Parallel. 
g-g. Inferior temporal. 
h, h. External perpendicular. 
i-i. Fronto-parietal ( calloso-marginal , Huxley). 
Jc-Ic. Internal perpendicular. 
4 E 
JJDCCCLXIV. 
