THE ANATOMY OF THE CHIMPANZEE. 51 



shown. The lower end of this fissure divides into two small branches which connect 

 with no other fissure. In tlie right hemisphere the posterior division almost cuts through 

 the gyrus separating it from the calcarine fissure. 



The calcarine fissux*e differs in one important respect in the two sides. In both it 

 ends in a. fork very near the hind end of the brain. On the left it opens into the Jissura 

 hypocttmin ; on the right it joins what seems to be a peculiar collateral fissure. A deep 

 fissure is seen in the cuneus, which, according to Kiikenthal and Ziehen, is very constant 

 in the chimpanzee. On the left the cuneus sends a convolution to the gyrus hypocampi 

 just above the end of the calcarine fissure ; on the right, owing to the peculiarity of the 

 calcarine fissure, this gyrus seems to run more directly into the gyrus hypocampi. 



The under side of the temporal lobe presents a very different appearance in its 

 anterior half, which is frankly inferior, and in the posterior portion, which slants into the 

 oblique inferior occipital surface. The former shows large simple convolutions. The 

 latter is broken up by many secondary sulci. The former shows the ends of the first and 

 second temporal convolutions passing obliquely forward from the outside of the brain 

 and behind them the third which is quite plain on the under surface of the left half, but 

 not clear on the right. The left collateral fissure is perhaps best described as splitting- 

 posterioi'ly into two parallel divisions. The lohulus lingualls lies between the inner of 

 these divisions and the fissura calcarina. Tlie lohulus fusiformis is between the two 

 divisions. 



On the right the Jissura calcarina runs obliquely outward across the under surface 

 of the temporal lobe to end in a short fissure which represents the separated anterior 

 portion oi Jissura collateralis. The posterior part of this fissure is in its j^roper place. 

 The lohulus lingualis is cut off by the abnormal direction of the Jissura calcarina. The 

 arrangement is, so far as I know, an undescribed one. 



EXPLANATION OF THE PLATES. 

 PLATE 7. 



Fig. 1. Foot. 

 Fig. 2. Hand. 



PLA'rE 8. 



Fig. 1. Caecum. Tlie appendix runs along the lower edge to the left of the caecum till lo.st to .sight behind the ileum. 

 Fig. 2. Inside of caecum. The ileo-caecal valve is seen above. Below this a valvular fold in the caecum, and still 

 lower the opening of the appendix. 



Fig. 3. The upper end of the left femur, showing a small, but distinct, thinl trochanter. 



PLATE 9. 



Fig. 1. The outer surface of the left hemisphere of the brain. 

 Fig. 2. The outer surface of the right hemisphere of the brain. 



