514 



is "höchstwahrscheiolich eine echte Hirnrinde". Nevertheless Edinger 

 held to the opinion that an undoubted cerebral cortex first appears in 

 the Reptilia ^). 



Two years later Nakagawa ^) found a group of cells at the dorso- 

 mesial angle of the cerebral hemisphere in certain Amphibia, which 

 he regarded as constituting a rudimentary cortical layer, and Edinger 

 suggested the probability of its homology with the "Ammonshorn", i. e. 

 the hippocampus. 



In the edition of his Lectures'') published in 1896 Edinger ex- 

 plains his views in these words, which follow an account of the structure 

 of the Frog's pallium, based on Pedro Ramon's researches: "Man 

 muß wohl diesen ganzen unregelmäßig disponierten Apparat als den 

 Ausgangspunkt einer Hirnrinde ansehen. Denn bei den Reptilien 

 findet man ganz die gleichen Elemente, aber in sehr viel größerer 

 Zahl und Dichtigkeit, auch regelmäßiger zu förmlichen Platten geordnet, 

 und bei diesen Tieren kann gar kein Zweifel mehr bestehen, daß man 

 es mit einer echten Rinde zu tun hat." (p. 136.) 



In his admirable contribution (Die Morphogenie des Zentral- 

 nervensystems) to Hertwig's Handbuch der vergleichenden und ex- 

 perimentellen Entwickelungslehre der Wirbeltiere (Bd. 2, Teil 3, 1906), 

 the late Professor K. v. Kupffer expressed the opinion that "das 

 Pallium wird erst bei den Reptilien durch eine bestimmte Schichtung, 

 die Formatio pallialis oder Rindenformation, charakterisiert" (p. 231). 



No serious objection could be urged in opposition to Edinger's 

 and V. Kupffer's statements, especially as they occur in books of 

 an expository nature, if there were no Dipnoi. 



But the walls of the cerebral hemispheres, both in Lepidosiren 

 and Protopterus, exhibit a structure, which, equally with that of the 

 reptilian brain, can be described in v. Kupffer's phrase as "eine be- 

 stimmte Schichtung, die Formatio pallialis". 



That this is no exaggeration is amply shown by Figures 1, 2 and 

 3, representing respectively a drawing of a coronal section through 

 the left cerebral hemisphere of an adult Lepidosiren, an untouched 

 photograph of the same section (including also the right hemisphere), 

 and the photograph of a similar section through an immature brain. 



The existence of this definite and unmistakable pallial formation 

 in such a lowly vertebrate is of great value in helping us to interpret 



1) Ueber die Entwickelung des Hirnmantels der Tierreihe. Archiv 

 für Psychiatrie, 1888. 



2) The Origin of the Cerebral Cortex. Journal of Morphology, 1890. 



3) Vorlesungen über den Bau der nervösen Zentralorgane, 1896. 



