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MR. J. L. CLARKE ON THE INTIMATE STRUCTURE OF THE BRAIN. 
feline tribe especially, is bent into a simple curve or loop. Fig. 35, Plate XI. represents 
a transverse section of the right anterior pyramid and olivary body of the Cat. On the 
outer side of the pyramid ( y ) is the olivary body, which consists of three masses of cells, 
the one in the middle (W) being a simple loop. Now in ascending the animal scale, I 
found that in the common Ape the olivary bodies are not only much increased in size 
and more prominent on the surface of the medulla, but that the loops or folds of the 
lamina, which are simple in the highest Carnivora, as the Cat, become thrown into 
secondary loops or convolutions, as at w, fig. 23, Plate X. Still higher in the scale the 
convolutions of the lamina are more numerous, and the bulk of the entire organ is 
much greater, as may be seen in figs. 36 & 37, Plate XI. The latter figure represents 
the right anterior pyramid (y) and olivary body (W) of a young Orang Outang*. Fig. 36 
was drawn from a transverse section of a piece of medulla given to me by the late Mr. 
Queckett, of the Royal College of Surgeons. From the strong resemblance of this 
medulla to that of Man, and the large size of the olivary bodies, it evidently belonged 
to one of the higher Simiadse. The olivary body itself closely resembles that of the 
Orang Outang (fig. 37) ; but it seems to be imbedded in the anterior pyramid, instead of 
lying behind and on its outer side. Moreover, there is another peculiarity in the exist- 
ence of a large separate column ( d ) forming part of the lateral column. In both this 
medulla and that of the Orang Outang (fig. 37), the convolutions of the olivary lamina 
are as numerous as in Man, and form a striking contrast to the simple loop of the 
Cat at W, fig. 35. On a former occasion I showed that in Mammalia generally the 
hypoglossal nerves are attached on the outer side of the olivary bodies, instead of on 
the inner side, as in Man. It is somewhat curious that in all the Apes, even in the 
Orang Outang and Chimpanzee, their point of attachment is intermediate, that is to say, 
they are attached to the olivary bodies themselves. 
I shall now proceed to describe the structures forming the upper part of the fourth 
ventricle. 
* For the medulla oblongata, pons Yarolii, and part of the cerebellum and cerebral convolutions of the Orang - 
Outang, I am indebted to the kindness of Dr. Muie, of the Zoological Gardens. 
