0)1 the Viscera of a Femah Chimpanzee. 803 



a transverse axis, so as to depress the anterior part 10°, 

 makes a difference of 5 in the index of the fissure, and so 

 reduces it to that of man. 



The fissure of Rolando passes outwards and forwards at 

 about the same angle as in man, and I am of opinion that its 

 position in relation to the anterior and posterior extremities 

 of the brain is practically the same as it is in the human 

 subject. 



Parieto- Occipital Fissure. — The arrangement of this fissure 

 in the chimpanzee has attracted the attention of numerous 

 anatomists, more especially since the appearance of Gratiolet's 

 classical " Memoire," in which the first annectant convolution 

 between the parietal and occipital lobes was described as 

 being absent in the chimpanzee, although well marked in the 

 orang. Further observations have not confirmed the view of 

 Gratiolet, and various anatomists ^ have recorded cases in 

 which the first annectant convolution was visible on the 

 superficial aspect of the brain. Professor D. J. Cunningham^ 

 has recently described this convolution as constituting a 

 distinct barrier to the communication between the internal 

 perpendicular fissure as it turns outwards on the hemisphere 

 and the intra-parietal fissure. Its relations in my specimen 

 agree with Cunningham's statement. The internal part of 

 the parieto-occipital fissure was separated from the calcarine 

 by a superficial annectant convolution. This convolution 

 appears to be very constant in the chimpanzee, although it is 

 absent or very rudimentary in man. 



The calcarine fissure gave rise to a large and prominent 

 hippocampus minor in the posterior cornu of the lateral 

 ventricle. 



Alimentary Canal. — The tongue is relatively longer and 

 narrower than in the human subject. In my specimen it 

 was 3 inches in length and 1^ inch in breadth. The 

 circumvallate papillae are described by Huxley ^ as being 

 disposed in the form of a T with the top turned forwards. 



1 Marshall, Nat. History Review, 1861, p. 211 ; Rolleston, Ihid., 1861, 

 p. 309 ; Turner, Proc. Roy. Soc. Edin., vol. v., p. 578. 

 ^ Jour, of Aiiat. and Phys., vol. xxiv., p. 149. 

 3 Medical Times and Gazette, vol. i., 1864, p. 487. 



