264 MORPHOLOGY OF THE CEREBRAL CONVOLUTIONS. 



reverse, he still follows the coronary suture in order to divide off the anterior or 

 frontal lobe. The parietal lobe, his Zwischenscheitelhim, he separates by a trans- 

 verse cut drawn perpendicular to the corpus callosum and across the hemispheres. 

 Still he remarks that for a future division he would choose the Hinterspalte 

 (parietooccipital fissure) and a cut passing from it through the outer and lower 

 surface of the hemisphere. Of the boundaries of the inferior lobe Huschke does not 

 speak. Reichert did not direct his attention to the division of the hemisphere into 

 the usual five lobes, because he does not believe that it is founded on any genetic 

 principles. He gives a representation of the hemisphere based on its embryological 

 development. He also regards the occipital lobe as a later development of the 

 hemisphere backward, and therefore only regards it as a secondary lobe. 



Sappey * recognizes only an anterior and a posterior lobe which are separated 

 by the fossa Sylvii and rejects the division posterior to the Sylvian fissure into a 

 temporal and occipital lobe. He does not note any separation at the upper and 

 inner surface. 



R. Wagner distinguishes a frontal, parietal, temporal and occipital lobe and 

 separates the latter above and on the mesial surface in the same manner as Gratiolet, 

 by means of the fissura perpendicularis interna (parieto-occipital.) 



Owen 2 defined the occipital lobe as that part which covers the posterior one- 

 third of the cerebellum and extends beyond it. This has, as was shown by Flower 

 and Huxley, no connection with the state of things as they exist in nature. 

 Pan sch separates the frontal from the parietal lobe by means of the fissura centra- 

 lis. He divides the parietal from the occipital lobe by means of the fissura perpen- 

 dicularis interna, whilst a boundary between the occipital and temporal lobes on 

 the lower surface does not, according to him, exist. 



Bischoff maps out on the cerebral surface the outlines of the different bones, 

 and believes that in this way the brain may be divided into principal parts or lobes. 

 He admits, however, that we cannot take this as a genetic relation and, therefore, 

 this division cannot be transferred to the relations existing in animals or in child- 

 hood, for neither comparative anatomy nor embryology would justify it. In his 

 descriptions, however, he follows the divisions into the usual five lobes which were 

 established by Arnold and Gratiolet. He places the posterior boundary of the 

 frontal lobe in front of the anterior central convolution instead of in front of the 

 central fissure ; for, as he remarks, this fissure with its surrounding convolutions 

 constitutes a whole, and the tearing apart of these two inclosing convolutions and 

 the placing of one in the frontal and the other in the parietal lobe is not natural. 

 He also considers that on the mesial surface of each hemisphere the boundary 

 between the frontal and parietal lobes is indicated by the anterior central convolution 

 passing into the longitudinal fissure. 



The parietal lobe he divides as previous writers have done, and it corresponds 



1 Traite" d'Anatomie descrip. 



2 Annals and Magazine of Nat. History, 1861. 



