58 Journal of Comparative Neurology. 



but in the black-snake that portion homologous with the hippo- 

 campus is relatively highly differentiated. Even the portions 

 corresponding to the fornicate and uncinate gyri may be distin- 

 guished, though there is, of course, no external indication of 

 the distinction. " 



On page i6, it is said that "the ventro-basal protuberance 

 of the hemispheres, which seems analogous with the pyriform 

 lobe of Rndents, for example, contains a concentric zone or hol- 

 low spheroid of gray matter greatly {though spmiously) resembl- 

 ing the hippocampus," 



Certainly there can be no ambiguity in this passage and we 

 are unable to find a passage which can be construed to indicate 

 a belief that the "occipito-basal lobe" corresponds to the "Am- 

 monshorn." 



In his first paper on the forebrain, Edinger calls attention 

 to the existence of a distinct bundle from the median wall of 

 the hemisphere to the diencephalon which he unhesitatingly 

 homologizes with the fornix. The median part of the mantle 

 contains a cortex characterized by the small size and close ar- 

 rangement of its cells. This corresponds to the region where 

 in mammalian embryos the arcuate fissure appears. At the 

 point where the median wall thins to form the plexus cho- 

 roideus the cortex is exposed. Between it and the margin of 

 the hemisphere is a protuberant ridge, in which are fibres. 

 This ridge Edinger identifies as the fornix ridge. The layer of 

 closely associated cells above it in the median wall of the hemi- 

 sphere is called Ammonsrinde or hippocampus. "Das betref- 

 fende Rindstuck muss man als erstes Auftreten der Ammons- 

 rinde in der Therreihe ansehen." "Sie enthalt also bei ihrem 

 ersten Auftreten alle die elemente, welche spater, wenn auch 

 durch Windungen und dergleichen verwischet, das character- 

 isch Ammonshorn bilden." 



On page 20 of this Journal for March, 1892, the relations 

 of the occipital cortex to the septum (intra-ventricular lobe) are 

 indicated. "In the meantime the free caudal margin of the 

 cortex has extended medianly, fusing with the intra-ventricular 

 lobe, completing a ring or cap of cortex, which entirely en- 



