THE BRAIN AND ITS MEMBRAS1.S. 



781 



posterior portion of the calcarine fissure is sometimes known as the lingual lobule 

 or gyrus. 



The fourth temporal convolution is of considerable length, and lies on the inner 

 aspect of the temporal lobe, between the collateral fissure above and the inferior 

 (third) temporal sulcus below, which latter separates it from the inferior (third) 

 temporal convolution on the outer surface of the temporal lobe. Its posterior part 

 is called, ar times, the fusiform lobule. 



The hippocampal convolution is the downward and forward prolongation, on the 

 mesial surface of the temporal lobe, of the gyrus fornicatus, just after the latter 

 has bent around and beneath the splenium of the corpus callosum. Its direction 

 is toward the apex of the temporal lobe, just before reaching which, however, its 

 anterior extremitv is recurved or bent backward in the form of a hook, which is 



FIG. 471. Side view of the brain of man, showing the localization of various functions. (After Ferrier.) 



I. Centre for movements of opposite leg and foot. 2, 3. 4. Centres for complex movements of the arms and legs, 

 as in swimming. 5. Extension forward of the arm and hand. 6. Supination of the hand and flexion of the 

 forearm. 7, S. Elevators and depressors of the angle of the mouth. 9, 10. Movements of the lips and tongue. 



II. Retraction of the angle of the mouth. 12. Movements of the eyes. 13, 13'. Vision. 14. Hearing, a, b, c, d. 

 Movements of the wrists and fingers. 



sometimes called the crochet or uncus. It is bounded below by the collateral Jis- 

 mtre (anterior portion), and above by the hippocampal or dentate fissure. 



The Uncinate Gyrus. The hippocampal and infracalcarine gyri are, taken 

 together, often described as one gyrus. the uitcinate. 



Besides the great primary convolutions above named and described, and 

 which can be recognized in almost any well-developed brain, there are a great 

 number of secondary convolutions which pass from one primary convolution to 

 another, and often render the arrangement of the latter somewhat obscure : of 

 these annc'-t'int <-,,/, r,,hitions the connections of the occipital lobe, above mentioned, 

 may be taken as examples. 



THE LIMBIC LOBE. By this term is understood a grouping together of certain 

 portions of the hemisphere which have a peculiar course. That is, beginning 

 anteriorly, they curve forward, upward, and backward, then downward and for- 

 ward, so that their two extremities lie quite close together. The structures of the 

 limbic lobe have all been described, and are as follows : (1) Gyrus fornicatus and 

 hippocampal gyrus : (2) the supracallosal gyrus (see below) ; (3) each half of the 



