THE ANAT0:MV of the CHIiLPANZEE. 47 



caecum is not unlike a human one, being broiider than long. It is a good example of 

 Treve's third chiss, namely, that commonly found in man. It is very different from that 

 figured by CTratiolet and Alix, which is long and tapering. A window cut in the dried 

 and inflated specimen shows an ileo-caecal valve extending obliquely upward and outward 

 from the inner side of the gut so as greatly to increase the size of that part of the 

 intestine which must be called the caecum. The slit is 2.4 cm. long. The valve is 

 continued about two thirds of the distance round the gut. Its greatest breadth is about 

 3 cm. Beneath it in the caecum, starting at the inner side from its under surface, is 

 another smaller fold which diverges from it. This is best marked toward the posterior 

 surface of the caecum. There is a small valve guarding the upper part of the 

 entrance of the appendix. 



The ascending colon is very large and strongly sacculated. 



The Brain. 



According to agreement, the brain was so hardened as to make it fit for microscopic 

 sections. The hemispheres were put at my disposal for the study of the convolutions. 

 The length, after hardening, is 11.2 cm., the breadth, 9.4 cm., the height, 6.7 cm. Seen 

 from the front there is a strong median downward projection of the frontal lobes where 

 they rest on the cribriform jjhites. This keel is much greater than in " Sallv," but 

 perhaps a little less than in Benham's^ figure of a common chimpanzee. The points which 

 at first sight are most noteworthy and characteristic of this particular brain are the large 

 size and diagrammatic appearance of the frontal and occipital convolutions in contrast 

 to the small size and complication through small fissures of the parietal and temporal 

 ones. There is a decided want of symmetry between the two halves. 



Fissure of Si/lvhcs. The main limb ends with a bifurcation on both sides of 

 the brain. On the left side the anterior limb is easily recognized. It runs forward 

 and ends in a bifui'cation, the two parts of which make a slight concavity around a 

 part of the third frontal, representing clearly enough the j»^«/'s triangularis, Broca's 

 promontory (pi. 9, fig. 1). In short, this is the Y plan often seen in the human brain, 

 only the arms of the Y are short and widely opened. On the right there is no 

 anterior limb at all, unless a depression on the third frontal in front of the praecentral 

 fissure can count as a rudiment. This is precisely where the fissure should be. The 

 little suhcentralis anterior and i\\e praeeentralis are behind it and the orhitofrontalis in 

 front of it. If the identification on the left side be correct, it will be observed 



' \ description of the cerebral convolutions of the cUiraiianzee known as ■■ Sally," etc. Qnart. journ. niicr. sc., Xov., 1804, 

 pi. 7. 



