1892.] NATURAL SCIENCES OF PHILADELPHIA. 209 



<;ampal fissure, the convolution of the hippocampus passing continu- 

 ously into the convolution of the corpus callosum, a disposition 

 sometimes observed in other anthropoids and monkeys, as in the 

 Chimpanzee, Gibbon and Spider Monkey, and which, with few ex- 

 ceptions, obtains in Man. The first occipital convolution, already 

 referred to as separating the parietal and occipital lobes, in winding 

 around the transverse occipital and the parieto-occipital fissures, 

 PI. XII, fig. 3P, forms an arch convex inward, then convex outward, 

 serving to connect the occipital Avith the parietal lobe, PI. XII, fig. 

 3 p, and more especially with the supramarginal lobule of the latter. 

 Hence the various names, annectant, bridging convolutions, premier 

 plis.de passage externe, obere immereScheitelbogen windung, given to 

 this convolution as well as that of first occipital convolution. 



This bridging or arching convolution is well developed in 

 both hemispheres of the brain of the Gorilla, that of the right 

 hemisphere being slightly less superficial than that of the left. On 

 neither side of the brain, PI. XII, fig. 3, of the Gorilla 

 can it be said, however, that there exists an operculum, 

 so striking a feature in the brain of the Chimpanzee and 

 of the lower monkeys. The second occipital convolution, lying 

 behind the transverse occipital fissure and outside the first 

 occipital convolution, passes into the parietal lobe and more partic- 

 ularly into the angular convolution of the latter. The third occip- 

 ital convolution, better denned on the right side than on the left 

 in the brain of our Gorilla, passes from the posterior extremity of the 

 hemisphere into the second and third temporal convolutions, PI. XI, 

 fig. 2 u, V. Unfortunately the inferior surface of the occipital 

 lobe of our specimen was too much altered to admit of exact descrip- 

 tion. Judging from what remains of it as compared with the cor- 

 responding part of the brains described by Bischoff'and Broca, the 

 lateral and median occipito-temporal convolutions must have been 

 present and well defined. The tempoi'al lobe, while distinctly sep- 

 arated from the frontal and parietal lobes by the Sylvian fissure, 

 passes without defined boundaries, as just seen, into the occipital 

 lobe and consists essentially of three convolutions. The superior 

 temporal convolution, PI. XI, fig. 2 t, lying between the fissure of 

 Sylvius and the superior temporal fissure, passes obliquely upward 

 and backward into the superior marginal convolution. The middle 

 temporal convolution, lying between the superior temporal and 



