496 



PEOF. G. ELLIOT SMITH ON THE MOEPHOLOGT OF THE 



One of the most recent writers upon the braiu in the Ampliibia (Pedro Ramon y Cajal, " L'Encephale 

 des Amphibiens," Bibliographie Anatomique, T. iv. 1896, p. 234.) described as basal ganglion the lower 

 half of the lateral (fig. 31, ^) and mesial (/5) walls together with the connecting band (7) which forms 

 the basal angle of the hemisphere in the Frog's brain (in a coronal section in front of the lamina 

 terminalis). The dorsal half of the mesial wall (S) he called " si-pUim," meaning to imply that it is the 

 homologue of the •' septum lucidum" of Human Anatomy. 



Fiir. 31. 



A still more recent writer (Ernst Gaupp, ' Ecker's uud Wiedersheim's Anatomic des Frosches/ 2ud 

 part, erste Halfte, 1897) described as •' basal ganglion " only that part of Eamon y CajaFs so-called 

 o-ano-lion which forms part of the lateral wall (a) ; and the mesial portion (/3) he called '•' septum.'' To 

 complicate matters further, Ramon's "septum" {h) Gaupp described as " A mmonshorn," i. e. hippo- 

 campus. Thus the only point upon which these two writers were in agreement is that the lower half of 

 the lateral wall (a.) is " basal ganglion." The brain of the Dipnoi is admittedly distinctly Amphibian, 

 and as regards the cerebral hemisphere the resemblance is very striking. It is interesting to note that 

 in Protopterus Rudolf Burckhardt (' Das Centralnervensystem von Protopterus annectens,' Berlin, 

 1892) regarded the upper part of the mesial wail of the hemisphere (8) (Gaupp's " hippocampus " and 

 Ramon's "septum") as the " basal ganglion" {vide Burckhardt, op. cit., Taf. 3. figs. 22 & 23). The 

 " Ammomhorn," or hippocampus, he located at the base of the hemisphere, where Ramon placed the 

 "basal ganglion " and Gaupp the " septum" and " basal ganglion" [vide Taf. 3. figs. 20 & 21). Ramon 

 (who in his most recent contribution [op. cit.) contradicted himself upon several occasions) added to 

 the intricacy of the present tangle by calling the mesial portion of his " basal ganglion," i. e. Gaupp's 

 "septum," the epistriatum (/S). The reason given by Ramon for this use of the latter term is that the 

 reo'iou /3 corresponds to the area so-named in reptiles by Ediuger. The enormity of the error involved 

 in this amazing statement will be appreciated, when I mention that the name " epistriatum " was applied 

 by Edinger to a portion of the lateral wall of the hemisphere in reptiles which is situated immediately 

 above the true basal ganglion. The structure iu question is the ventral part of the " pallium." It is 

 inconceivable how Ramon can see in the lower portion of the mesial wall, moreover, iu a region which 

 he himself calls " basal ganglion," a homologue of Ediuger''s epistriatum. In the same memoir Ramon y 

 Cajal describes as the homologue of the hippocampus the same region which he called " septum " 

 elsewhere. 



It would be possible to multiply examples almost without limit to show that even at the present time 

 the problems of the morphology of the cerebral hemisphere in the Amphibia are iu the apparently 

 hopeless state of confusion, of which this single striking instance is unfortunately typical. 



In view of the above statements it would clearly be mere waste of energy seriously to discuss further 



