552 
which may therefore be termed occipital, never possesses any rela- 
tion whatsoever to the cerebrum. 
An examination of several members of most of the great orders 
of the class Mammalia has satisfied me, that it is quite possible to 
arrive in them at as correct a conception of the relations of the 
cerebrum to the cerebellum as in man. In every animal which I have 
examined, I have found the cerebellum to possess two surfaces. One 
of these is in contact with the tentorium, and, through the interven- 
tion of that membrane, is in relation to the cerebrum. The other 
is in contact with the wall of the occipital fossa. The surfaces are 
distinguished from each other by looking in different directions. 
The tentorial, corresponding to the superior in man, looks, as a rule, 
more or less forwards. The occipital, corresponding to the inferior 
in man, looks, as a rule, more or less backwards. These surfaces 
along their line of junction form an angle, more or less marked in 
different animals. This angle coi’responds to the circumference, or 
posterior margin, of the human cerebellum, and is in contact with 
the line of attachment of the tentorium to the occipital bone. The 
tentorial aspect of the cerebellum, therefore, is that which is in con- 
stant relation to the cerebrum, and, not only in man, but in all the 
mammalia, is covered by it. 
That this is the case with regard to the Quadrumana, has been so 
completely proven by the observations of the various anatomists 
already referred to, that it appears almost unnecessary to enter again 
into this question. As I have had an opportunity of dissecting in 
situ the brain of a young and recently dead Cercopithecus, which 
was given me by my friend Dr M c Bain, I may mention that in it 
the posterior cerebral lobes not merely covered the tentorial surface 
of the cerebellum, but projected decidedly beyond its posterior 
margin. Through the liberality also of Professor Goodsir, I have 
obtained permission to examine several quadrumanous brains in his 
possession. All these had been removed from the cranial cavity, 
and had been lying for some time in spirit. 
In a Chimpanzee, the tentorial surface of the cerebellum was 
directed upwards, and was evidently flatter than the corresponding 
surface in man. The occipital surface was directed downwards. 
The posterior margin was clearly marked. The posterior lobes of 
the cerebrum corresponded to the whole of the tentorial surface, and 
extended as far as the posterior margin of the cerebellum, beyond 
