MORPHOLOGY OF THE CEREBRAL CONVOLUTIONS. 



299 



Fig. 9. 



the smaller important portions as lobules much mislocation and confusion are 

 avoided. Thus the portion, Pis. XLII, fig. 2 and XLI V, fig. 2 x, directly beneath 

 the calcarine fissure and posterior to the position of the hippocampal, h.p., has been 

 termed by Huschke the lobulus lingualis {Zimgenldppchen) . It is the iintere inner e 

 Hinterhauptswindimgsgrttppe of Bischoff. The anterior portion, H, is called by 

 most writers the gyrus hippocampi; it is the pli unciforme or temporal moyen in- 

 terne et lobule de l' hippo campe of Gratiolet; the fourth temporal, vierte Schldfen- 

 windung of Bischoff; the uncinate gyrus of Huxley. This division of M.O.T. 

 into two convolutions, as though they were separate and distinct, and without 

 recognizing it as a whole, seems to me not to represent the true relations and. at 

 the same time, serves to give false notions with respect to the arrangement of the 

 convolutions found in this region. 



As, however, it may be convenient for purposes of description to name the two 

 portions, H. and X., separately, the former may be designated as the anterior or 

 hippocampal and the latter as the posterior or calcarine portions of the mesial 

 occipito-temporal convolution; always recognizing, however, that they represent 

 but one and not two separate and distinct convolutions. 



The occipito-temporal lobe consists, therefore, of four occipito-temporal convolu- 

 tions separated from each other by three occipito-temporal fissures. Of these, two con- 

 volutions and two fissures are found en- 

 tirely upon the lateral surface, one con- 

 volution and one fissure entirely upon 

 the mesial surface, whilst the remaining 

 convolution, the third or inferior occip- 

 to-temporal is found extending from 

 the lateral through the inferior on to 

 the mesial surface. The arrangement 

 and relations to the other lobes of the 

 brain may be seen in the accompany- 

 ing figures 9 and 10, which can be com- 

 pared with the figures in the various 

 plates. It will be seen from this, that 

 the fissures of the occipito-temporal 

 lobe with their accompanying convolu- 

 tions form together a symmetrical 

 whole, which is related to the structure 

 of the occipital lobe in a perfectly defi- 

 nite manner and according to a fixed 

 morphological type, which I farther 

 on will attempt to show is also the 

 type upon which the occipitofrontal 

 lobe is built. 



Fig. 10. 



