522 PROFESSOR MARSHALL ON THE BRAIN OF A BTTSHWOMAN ; AND 
gradually backwards, being 1-1 inch in length, and *4 inch in greatest breadth. The 
eminentia collateralis (g) is represented by a broad triangular and elevated surface 
between the two hippocampi. 
On the method employed by Mr. Flower to determine the ratio between the antero- 
median and posterior portions of the cerebrum, measured forwards and backwards from 
the point of junction of the hippocampi, I find that the antero-median portion measures 
3*75 inches, and the posterior 2-05 inches, showing a ratio of 100 to 54*6 ; whilst the 
ordinary ratio in the European is said by Mr. Flower to be 100 to 53 ; in the Chim- 
panzee it is as 100 to 52 ; so that in the Bushwoman the posterior region (thus measured 
on its under surface) is proportionally longer, or the antero-median region propor- 
tionally shorter than in the European or Chimpanzee’s brain ; but in other Quadrumana 
the posterior region is stated to be longer still (in Hapale 100 to 62). 
As seen in the body of the ventricle, the corpus striatum ( h ) and optic thalamus (a) 
occupy about the same relative spaces from before backwards as in the European ; but 
both, especially the optic thalamus, appear narrower from side to side. In an ordinary 
European brain, the exposed part of the corpus striatum measured *9 inch long and 
•5 inch wide; the optic thalamus T3 inch long and *5 inch wide. In the Bushwoman 
the corpus striatum is *9 inch long and *3 inch wide, and the optic thalamus T2 inch by 
*45 inch. 
The corpora quadrigemina (Plate XVIII. fig. 4, q) are rather small, even in propor- 
tion to the brain ; the anterior one, as usual, is the more prominent, and the posterior 
one the wider of the two. The corpora geniculata are both well marked, though of 
moderate size. The pineal body is small ; its habenulae are well developed. The 
corpora albicantia are prominently developed. The pituitary body is of moderate size. 
The pons Varolii seems proportionally large : from its upper to its lower border it 
measures *9 inch, whilst in the European brain it is about 1 inch ; the mean thickness 
of its section is, in the Bushwoman’s brain, *8 inch; in the European, *9 inch. 
The medulla oblongata is relatively wide, and so are the cerebral peduncles. The 
medulla oblongata is *85 inch wide at its widest part, offering the ratio of 1 to 6, 
instead of the ordinary ratio of 1 to 7, to the width of the cerebrum. Upon the medulla 
oblongata the anterior pyramids are well pronounced, and the corpora olivaria are narrow 
but prominent : the corpus dentatum within the latter is neatly defined and waved. 
The cranial nerves generally appear small ; the olfactory nerves, however, are well 
developed. The optic nerves, commissure, and tracks are small and flattened, even 
the nerves having an unusually thin oval section. The small size of the optic tracks and 
corpora quadrigemina is interesting in connexion with the defective development of 
the occipital lobes of the cerebrum, a part to which many of their fibres have been traced 
by Gratiolet. 
The cerebellum . — Every part of the cerebellum (Plates XVII. & XVIII. figs. 2, 3, 4, Ce) 
is present. The lateral portions or hemispheres are especially wide. On the upper sur- 
face the square lobes are not so square as usual, but are elongated laterally, and narrow 
