NATURAL SUBDIVISION OF THE CEREBRAL HEMISPHERE. 435 



- because this hybrid term more ai3tly describes its relation to 



the lamina terminalis in many of the lowlier vertebrates. (For 



a fuller account of this body, see " The Pielation of the Fornix 



to the Margin of the Cerebral Cortex," this Journal, vol. xxxii.). 



,(6) The locus perforatus anticus calls for no special mention. 



(7) The hippocampal formation presents the well-known 

 peculiar structure which is quite distinctive. Under this 

 heading we include not only the hippocampus {scnstc stricio), 

 but also the fascia dentata, the hippocam'pus imdus (Zucker- 

 kandl's " Balkenwindung "), the supra- and pre-callosal vestiges 

 of the hippocampus and the fornix (fimbria) (figs. 3 and 4). 

 Vide Jotir. of Anat. and Phys., vol. xxxii., op. cit. 



(8) The corpus striatum is a ganglionic mass, which is 

 excluded from participation in the surface of the hemisphere 

 by the tubercuhim olfactorium below, and by part of the 

 pyriform lobe, and part of the neopallium upon its lateral 

 aspect. 



(9) The region which I have called " neopallium " presents 

 a structure which is different from that of any of the eight other 

 histological formations in the cerebral hemisphere. It presents, 

 in fact, those peculiar characters, that distinctive gradation of 

 pyramidal cells, which one generally associates with the idea 

 of the typical cortex and its medulla. And although different 

 parts of this neopallium exhibit undoubted specialisations of 

 structure, especially in the more highly organised mammalian 

 brains, these differences in texture are so slight in comparison, 

 say, to those which distinguish the pyriform lobe or the hippo- 

 campus from the neopallium, that they may be neglected in a 

 primary subdivision of the hemisphere into its fundamental 

 parts. 



More than forty years ago Eeichert came to the conclusion 

 (in a work ^ dealing more especially with the development of 

 the human brain) that it would facilitate the accurate descrip- 

 tion of the cerebral hemisphere if the thin upper j)art of the 

 walls of the embryonic cerebral vesicle, which he termed 

 " pallium '' (mantle), were distinguished from the thicker basal 

 mass which he called the " Stammlappen" The latter expres- 

 sion was so employed as to include the locus perforatus anticus, 

 ^ Der Ban d. mcnsch. Gehirns, Berlin, 1859. 



