2*10 PROCEEDINGS OF THE ACADEMY OP [1884. 



of Goette's important observation ^ that in the batrachia the 

 epiphysis proper loses its primitive connection with the brain, 

 and lies external to the skull, while its primitive union with the 

 brain is indicated by the more or less degenerate walls of the 

 epiphysial tube. Yet Goette's figures do not give such a clear 

 history of these changes, as the importance of the subject demands, 

 and so far as we know, there have been no embryological investi- 

 gations on this subject among the urodela. 



In the meantime, since the publication of Goette's discovery, 

 many general works ^ by different writers upon comparative 

 anatomy have appeared, all of which figure the epiphysis as a 

 conspicuous object lying between the cerebral hemispheres. There 

 can be little doubt that these, as well as all the earlier writers 

 upon the Amphibian brain, such as Wyman, Ecker, Leidig, Rathke 

 and Stieda have mistaken the remarkable upgrowth of the vascular 

 plexus above the prosocoelia for the epiphysis, and that this bod3^ 

 in the urodela, as well as in the batrachia, is represented upon the 

 brain surface merely- by a portion of its primitive stalk. The 

 grounds for this statement, so far as it concerns the urodela, are 

 that in Amphiuma, Menobranchus and Menopoma portions of this 

 primitive stalk can be seen in vertical section, in different stages 

 of arrest, and retaining to a greater or less extent the primitive 

 condition of a glovefinger-like upfolding of the brain roof. 



In the discovery of the supracommissura and the invariable 

 position of the recessus pinealis, between this and the post- 

 commissura, we find unmistakable anatomical evidence for Goette's 

 conclusions, although we are not thereby warranted in assuming 

 that the development of the epiphysis is the same in the urodela as 

 in the batrachia. All doubt is also removed as to the connection 

 between the stalk of the epiphysis and the supraplexus, as the 

 latter is clearly distinct from the former, and does not establish 

 such close relations with the stalk as in the birds. 



In Menopoma (fig. 4) the ependyma cells upon either side of 

 the recessus become much enlarged and elongated ; upon the 

 upper surface of the brain they lose this character, becoming 



^ Entwickelungsgeschichte der Unke, 1875, p. 283. 



' Huxley and Martin's Practical Biology, Wiedersheim's Lehrbuch der 

 vergleichenden Anatomic and Wilder' s Anatomical Technology may be 

 cited as examples. 



