208 PROCEEDINGS OF THE ACADEMY OF [1892. 



taken together as correspondiug to the parieto-occipital fissure in 

 the brain of Man, supposing the latter to be broader and bridged 

 over by the first occipital convolution. It appears to us, however, 

 as more probable that the internal occipital fissure alone in the 

 Gorilla should be regarded as homologous with the parieto-occipital 

 fissure in Man, the external occipital fissure in the Gorilla corre- 

 sponding to the fissure described in the brain of Man as the trans- 

 verse occipital fissure. That the latter view is the correct one is 

 still further shown by the fact already referred to of the parietal 

 fissure passing into the transverse occipital fissure, which is often the 

 case in Man. On the mesial, as well as upon the superior surface, 

 the occipital is as distinctly separated from the parietal lobe by the 

 parieto-occipital fissure in the brain of the Gorilla as in the brain of 

 Man. It should be mentioned, however, that in the brain of the Gor- 

 illa the parieto-occipital does not reach the calcarine fissure, as is usu- 

 ally the case in the brain of Man, the two fissures being separated 

 by a distinct convolution, the "deuxieme plis de passage interne" 

 of Gratiolet, the " untere immere Scheitelbogen windung" of 

 Bischoff: That is, the part of the occipital lube described in the 

 brain of Manas the wedge-shaped convolution or cuueus is divided 

 in the brain of the Gorilla into an upper and larger, and a lower and 

 smaller portion. A similar disposition usually obtains in the brain 

 of the anthropoids and the lower monkeys, though this convolution 

 may be absent on one side at least, as was observed by the author^ 

 in the case of a Chimpanzee. On the other hand, it should be men- 

 tioned, as stated several years ago by the author'^ in a comnumica- 

 tion made to this Academy, that he had observed this convolution, 

 that is, the " deuxieme plis de passage interne " of Gratiolet, in the 

 brain of Man, and he takes this opportunity of calling attention to 

 its presence in the brain of the white man as well as in that of the 

 negro. 



The calcarine fissure in the brain of the Gorilla passed into the 

 hippocampal fissure, the convolution of the hippocampus being 

 thereby separated from the convolution of the corpus callosum. In 

 this respect the brain of the Gorilla agrees with that of the remain- 

 ing anthropoids and lower monkeys, in which the calcarine usually 

 passes into the hippocampal fissure. In the brain of the Gorilla 

 described by Broca, however, the calcarine did not reach the hippo- 



1 Proceedings A. N. S., Pnila., 1879. ' 



2 Proceedings A. N. S., Phila., 1880. 



