520 Journal of Comparative Neurology and Psychology. 



The nervous portion of the hemisphere includes numerous struc- 

 tures the arrangement of which will be spoken of in the next section 

 on nomenclature. The term pallium has been loosely used by various 

 authors for the membraneous roof of the telencephalon, the dorsal 

 part of the nervous portion and the superficial cell layers in the 

 nervous portion. Edinger uses it in all these senses and in the last 

 edition of his textbook (1908, Bd. 2, p. 249) he distinctly states 

 that the epithelial roof of the teleostean telencephalon is the pallium. 

 "Dieses Dach der Hirnblase heisst Himmantel, Pallium cerebri. 

 Dazu gehort auch der auf Fig. 220 noch rein epithelial gebliebene 

 Abschnitt, derselbe, welcher schon bei den Selachiem und Amphibien 

 aus eigentlicher Gehirnsubstanz besteht." This ambiguity is very 

 unfortunate. Since we have the convenient term tela for the mem- 

 braneous roof of the forebrain, the term pallium should be reserved 

 for the cerebral cortex. The question, then, whether teleosts (or 

 other forms) possess a pallium should be answered, not with Kabl- 

 Riickhard by pointing to the membraneous roof, but by ascertaining 

 whether there is present any nervous substance whose fiber connec- 

 tions and functions warrant its being compared with the cortex of 

 higher forms. 



It is still too early to define in an exact way what is meant by 

 cerebral cortex. It is not sufficient to define it as superficial layers 

 of cells in the telencephalon because in all classes of vertebrates and 

 in man, superficial gray matter is found in the forebrain whose 

 fiber connections and functions are very different from those of the 

 true cortex. To say that the cortex consists of superficial gray in 

 the roof or dorsal wall of the forebrain gives no means of deter- 

 mining its extent or boundaries. Although the term cortex implies 

 and was first used for superficial layers, it has come in recent years 

 to signify the brain substance which constitutes certain functional 

 mechanisms, whether superficial or not. It is necessary to define the 

 cortex by its fiber connections and from the functional point of view. 

 In mammals the general cortex is understood to be a collection of 

 highly complex centers which exercise functions of correlation and 

 control over bodily movements, etc., through lower sensory and motor 

 centers. The sensory impressions coming to these cortical centers 



