557 
If one might form an opinion, from the casts of the cranial cavities 
of these animals, of the size of their posterior cerebral lobes, it is 
not improbable that they might be found to possess indications of 
posterior horns to the ventricles. I shall certainly avail myself of 
the first opportunity which may present itself, to inquire into this 
point. Besides, I find that Tiedemann in his “ leones,” p. 19, in 
a description of the brain of a Phoca vitulina, states, “ prsetersea 
cornu posterioris vestigium occurrit.” 
Of the Pachydermata and Buminantia, I have examined in situ the 
brains of the pig and sheep. In both these animals the tentorial 
and occipital surfaces of the cerebellum were clearly indicated by 
the line of attachment of the tentorium to the occipital bone. In 
both, the cerebral hemispheres extended backwards as far as that 
line, so that the tentorial surface of the cerebellar hemispheres was 
completely covered by it. In the pig, the tentorial surface of the 
cerebellum was larger proportionally than in the sheep, so that the 
extent of cerebrum in relation to the cerebellum was greater. 
When the brain of either animal was examined from above, a partial 
projection of the cerebellum behind the cerebrum might be seen ; 
but the exposed surface was the occipital, and not the tentorial. 
From an examination of the brains, preserved in spirit, of the Wart- 
hog ( Phas co-chcer es ) and Peccari ( Dycoteles ) in the possession of 
Professor Goodsir, it would appear, that in them, as in the common 
pig, the tentorial surface is covered by the cerebrum. 
In the Bodentia, Insectivora, Cheiroptera, and Marsupialia, the 
cerebellum is no longer placed below the cerebrum, but behind 
it, so that it becomes really a cerebellum posterius. From 
the statements which have been made in the works of several 
anatomists of great distinction, it would appear to be their opinion 
that the cerebrum has, in these orders, so slight a relation to the 
cerebellum, that the corpora quadrigemina are more or less exposed 
between the two.* From an examination which I have conducted 
in situ , of the brains of several members of these important groups, 
I think it very doubtful whether such a general statement is correct. 
Of the Bodentia, I have examined the rabbit, guinea-pig (Caviacobaid ) , 
and rat. In all these animals it was quite possible to distinguish a 
tentorial and occipital surface in the cerebellum. The area of the 
* Tiedemann, Anatomie des Gehirns, p. 146; leones, p. 48. Cruveilhier, 
Descriptive Anatomy, p. 1013. Stannius, Lehrbuch, pp. 389, 390. 
