THE CEREBRUM 573 



post-central convolution. Passing backward, it winds around the 

 superior extremity of the fissure of Sylvius, in which situation it is known 

 as the supra-marginal convolution. Beyond this point it divides into 

 two portions, one of which runs forward into the temporal lobe above 

 the super-temporaj fissure, while the other runs downward and back- 

 ward, following the intra-parietal fissure to its termination. At this 

 point it makes a sharp bend and runs forward into the temporal lobe 

 just beneath the super-temporal fissure. In the neighborhood of the 

 bend it is generally known as the angular convolution or gyrus. 

 The Temporo-sphenoidal Lobe. The temporo-sphenoidal lobe presents 

 in its external surface three well-marked convolutions: viz., the super-, the 

 iedi-, and the sub-temporal, separated by the super- and medi-temporal 

 ssures. These three convolutions are in a general way parallel with each 

 ther, and pursue a direction from before backward and upward. Ante- 

 Lorly, they are fused together, but posteriorly their connections are some- 

 hat different. The super-temporal is continuous behind and above with 

 ae supra-marginal convolution, and behind and below with the angular 

 onvolution or gyrus. The medi-temporal blends with the preceding am 

 Vith the middle occipital. The sub-temporal is continuous with the 



erior occipital. A 



The Occipital Lobe. The occipital lobe is triangular in shape and 

 orms the posterior apex of the hemisphere. Its base on the externa 

 urface is formed by an imaginary line drawn from the paneto-occiptal 

 issure to the pre-occipital notch on the inferior and lateral border. 1 he 

 eternal surface presents three convolutions the superior, middle, am 



