On tliG Viscera of a Female Chimpanzee. 299 



weight of 29 children between two and four years of age to 

 be 38'71 ounces. 



Although we have no direct evidence as to the weight of 

 the brain of the adult chimpanzee, we can form a very fair 

 estimate by an examination of its cranial capacity. Accord- 

 ing to Topinard ^ this varied in three females from 387 cc. 

 to 425 cc. Mr James Simpson, assistant in the Anatomical 

 Museum of the Edinburgh University, very kindly measured 

 the cranial capacity of my chimpanzee. He employed 

 Sir Wm. Turner's method,^ and found it to be 360 cc. It 

 thus appears that the increase in the cranial capacity of the 

 chimpanzee is not very great after the commencement of the 

 second dentition, and had my specimen lived until it was an 

 adult, its brain would probably have weighed about 15 ounces. 

 The averao:e w^eioht of the adult human female is about 

 44 ounces. 



In my specimen the cerebrum completely overlapped and 

 extended backwards about quarter of an inch behind the 

 cerebellum. It is unnecessary that I should discuss this 

 question, even although such recent writers as Chapman^ 

 and Mtiller * describe the posterior part of the cerebellum as 

 being uncovered by the cerebrum, for D. J. Cunningham,^ 

 by freezing the entire head and making sections of the brain 

 in situ, has conclusively demonstrated that the cerebrum 

 does completely overlap the cerebellum. In Muller's case 

 the cerebellum is described as projecting 3 mm. beyond the 

 cerebrum, but an examination of the drawings which he 

 gives of the brain will readily show tliat he has unduly 

 depressed the anterior part of this organ, and had he placed 

 the brain in the skull with the face directed forwards, he 

 would have found the cerebrum to reach farther back than 

 the cerebellum. 



The fissures and convolutions of the chimpanzee's cerebrum 



1 Anthropology, 1878, p. 50. 



- "Challenger" Reports — Zoology, pt. xxix., p. 9. 



3 On the Structure of the Chimpanzee— Proceedings of the Acad, of Natural 

 Science of Philadelphia, 1879. 



•* Zur Anatomic des Chimpansgehirn — Arch, fiir Anthropologic, Bd. xvii., 

 1888. 



^ Koyal Irish Academy— "Cunninghum IMemoirs," No. 2, 1886. 

 VOL X. X 



