NERVOUS SYSTEM. VERTEBRATA. 451 



superior, and the crucial as the representative of the 

 central (Rolando's) sulcus. Such being the case, it is not 

 altogether surprising to find in two mammals, which 

 possess brains of approximately the same size, although 

 they have diverged so widely as the Bear and the Gorilla, 

 that this central region of the hemispheres has retained 

 some resemblance, even though the frontal and occipital 

 poles have become so vastly altered. Even if it be partly 

 fortuitous, there can be no question of the essential identity 

 of the chief features of these regions say in specimen 

 D. 365 (Bear) and this Gorilla's brain. Even the peculiar 

 curves of the crucial (central) sulcus and its relations to 

 the precrucial (precentral), to the ansate (ramus post- 

 centralis) and lateral (intraparietal) are curiously reproduced 

 in each hemisphere. 



The paraflocculi are equal to the flocculi in size and are 

 freely exposed. 



Beddard, op. cit. p. 72, fig. 6. 



D. 662. Two casts of the cranial cavity of a young Gorilla 



(Anthropopithecus gorilla). 



D. 663. Two casts of the cranial cavity of an adult Gorilla 

 (Anthropopithecus gorilla). 



These are of interest as showing the exact shape and 

 especially the degree of rostration of the cerebral hemi- 

 spheres. 



D. 664. The brain of a Chimpanzee (Anthropopithecus troglo- 

 dytes), (<?). 



Apart from the difference in size there is little to dis- 

 tinguish the brain of the Chimpanzee from that of the 

 Gorilla. If, however, the four specimens of Gorilla-brains 

 in this Collection be compared with the ten specimens of 

 Chimpanzee-brains, it will be noticed that the Simian cleft 

 or Affenspalte is much more complete and Cercopithecoid 

 in the Chimpanzee than it is in the Gorilla. At the same 

 time, one must not hastily conclude that the Gorilla's brain 

 is therefore more like the human than is that of the Chim- 

 panzee, for, as specimens D. 666 & D. 667 show, the brain 



2 G 2 



