4o6 'Journal of Comparative Neurology and Psychology. 



Smith. ^ He presents in the work cited a very cogent argument 

 for extending the appHcation of the word rhinencephalon to com- 

 prise the whole olfactory apparatus, including the olfactory cere- 

 bral cortex, or archipallium. This course has much to recommend 

 it, for the olfactory cerebral cortex is more intimately connected 

 with the lower olfactory centers than are the cortical representa- 

 tions of the other sensory systems with their lower centers. In the 

 case of the latter functional systems the cortical centers are widely 

 separated topographically from their respective lower centers, so 

 that the cortex cannot be joined to the lower centers in a regional 

 subdivision of the brain. For the sake of uniformity it seems to 

 me better to treat the entire cerebral pallium in the same way, even 

 though the limits between olfactory pallium and lower olfactory 

 centers cannot always be clearly drawn, as Elliot Smith has 

 shown. 



I, therefore, recommend that the rhinencephalon be limited to 

 the basal or stem portion of the olfactory system and that the olfac- 

 tory pallium be excluded from the rhinencephalon. The olfactory 

 pallium is indeed very distinct structurally as well as physiolog- 

 ically, from the remainder of the cerebral cortex and therefore the 

 separation of the cortex into archipallium and neopallium is 

 worthy of recognition in our nomenclature. The usage here rec- 

 ommended is apparently similar to that of the BNA, but Elliot 

 Smith has shown in the paper cited that neither Professor His as 

 reporter for the BNA nor the neurologists who have subsequently 

 adopted his terms are consistent in their use of them. 



Confusion of this sort can be avoided only by establishing a 

 definition of pallium which is independent of accidental form rela- 

 tions. The term was first applied to the thin free forebrain roof, 

 as contrasted with the more massive basal ganglia. In lower 

 vertebrates this criterion is of no morphological value. Kappers 

 and Theunissen'' have developed in a fruitful way a histological 

 conception of the distinction between pallium and basal forebrain 

 centers. In the case of the olfactory system the primary and sec- 

 ondary olfactory centers are considered as belonging to the basal 

 or stem portion of the telencephalon, while olfactory centers of 



^G. Elliot Smith. Notes upon the natural subdivision of the cerebral hemisphere. Journ. Anat. 

 and Physiol., vol. 35, no. 4, pp. 431-454, 1901. 



^ Zur vergleichenden Anatomic des Vorderhirnes der Vertebraten. Anat. Anz., Bd. 30, 1907; and 

 Die Phylogenese des Rhinencephalons, des Corpus striatum und der Vorderhirnkommissuren. Folia 

 Neuro-hiologica,\'o\. I, no. 2, 1908. 



