ii THE POSTERIOR LOBES. 137 



the Chimpanzee " in the Natural History Review for 

 July, 1861. The sharper definition of the lower edge of 

 the east of the cerebral chamber in the Chimpanzee arises 

 from the circumstance that the tentorium remained in 

 that skull and not in the Man's. The cast more accurately 

 represents the brain in the Chimpanzee than in the Man; 

 and the great backward projection of the posterior lobes 

 of the cerebrum of the former, beyond the cerebellum, is 

 conspicuous. 



tion of the skull of any ape above a Lemur, without 

 taking the trouble to make a cast of it. For there 

 is a very marked groove in every such skull, as in 

 the human skull — which indicates the line of at- 

 tachment of what is termed the tentorium — a sort 

 of parchment-like shelf, or partition, which, in the 

 recent state, is interposed between the cerebrum 

 and cerebellum, and prevents the former from 

 pressing upon the latter. (See Fig. 17.) 



This groove, therefore, indicates the line of 

 separation between that part of the cranial cavity 

 which contains the cerebrum, and that which 

 contains the cerebellum; and as the brain exactly 

 fills the cavity of the skull, it is obvious that the 

 relations of these two parts of the cranial cavity 

 at once informs us of the relations of their con- 

 tents. Now in man, in all the old world, and in 

 all the new world Simias, with one exception, when 

 the face is directed forwards, this line of attach- 

 ment of the tentorium, or impression for the lateral 

 sinus, as it is technically called, is nearly hori- 

 zontal, and the cerebral chamber invariably over- 

 laps or projects behind the cerebellar chamber. 



