258 MORPHOLOGY OF THE CEREBRAL CONVOLUTIONS. 



corresponding with the lobulus lingualis of Huschke and the gyrus hippocampi 

 of Gratiolet, Wagner, etc.; also a gyrus occipito-temporalis medius, equivalent to 

 the lobulus fusiformis of Huschke. The attention of Pansch in these researches was 

 directed principally to ape's brains. Since then Pansch has published another 

 paper 1 in which he insists that in Man and the apes there is a natural system of 

 the convolutions, that is, a practical division of the cerebral surface which does not 

 depend upon chance but upon genetic principles. He considers it questionable 

 whether the division into lobes as usually designated is founded upon genetic prin- 

 ciples. He is of the opinion that the division produced by the ramus ascendens of 

 the fossa Sylvii is just as important as that produced by its posterior or horizontal 

 branch, and he believes that the outer surface of the hemisphere may be divided 

 by means of the Sylvian fissure considered as follows : an anterior portion 

 lying in front of the ramus ascendens, a middle or upper portion lying posterior to 

 it, and a lower or inferior part lying below the horizontal branch of the fissura 

 Sylvii. He says that the significance of such a division by means of the ramus 

 ascendens has never yet been given, or where it has, a misunderstanding has been 

 the basis of it. This ramus ascendens he asserts must be the fissure next in 

 importance to the horizontal branch of the fossa Sylvii which we must take into 

 account in a division of the brain surface. Amongst the other furrows he recog- 

 nizes no genetic differences, the only distinction being, according to him, as regards 

 the time of their appearance ; or to express it more generally, in the greater 

 or less pertinacity of form and position ; but he regards these differences as merely 

 relative. 



Pansch takes his type of the arrangement of the fissures and convolutions from 

 their manner of development in the human embryo. He compares the system as 

 thus deduced with the conditions as found in the adult human brain and with the 

 brains of the lower Primates. He regards the fossa Sylvii as laying down the fun- 

 damental divisions of the hemisphere. The other fissures he divides into primary 

 and secondary sulci. He notices the early appearance on the mesial surface of the 

 fissura horizontalis or calcarine. the fissura perpendicularis interna or parieto-occi- 

 pital and also a furrow, which separating the corpus callosum from the hemisphere 

 and extending downward into the temporal lobe, produces finally a separation of 

 the so-called uncus from the rest of the surface. He terms this sulcus, after the 

 English anatomists, the fissura dentatus (fissura hippocampi) and fissure around the 

 corpus callosum. 



On the lateral surface, he distinguishes four fissures which, fan-shaped, sur- 

 round the fossa of Sylvius. He calls these after Reichert, the primary radiating 

 furrows. The first -three of these lie on the anterior lateral portion of the hemis- 

 phere and are included between the two branches of the Sylvian fissures. The 

 fourth lies parallel to the fissures of Sylvius and between it and the inferior border 



1 Ueber die typische Anordnung der Furchen und Windungeu auf den Grosshirnhemispharen des 

 Menschen und der AffeD. Archiv. fur Anthropologic, 1879. 



