Herrick, Neurological Laboratory Notes, 59 



closes the axial lobe, which latter, by the encroachments of the 

 ventricle, has become separate from the wall. The cells of the 

 occipital cortex resemble those of the fronto-median lobe." 



While, therefore, the writer independently identified much 

 the same region as that called by Edinger Ammons cortex with 

 the hippocampus, it will be seen that it is rather the caudal than 

 the mesal region which is thus identified ; while Dr. Edinger 

 seems to include the whole median wall as far forward as the cal- 

 losum and does not specifically include the occipital cortex. A 

 comparison of the hippocampus of reptiles with that of the 

 opossum is exceedingly instructive. In the latter case, where 

 the callosum is not developed to the extent characteristic of 

 higher mammals, the relations are identical with those of reptiles 

 except that the backward development of the cortex has folded 

 the free caudal margin upon itself. (See plates A, B and C, 

 Vol. II., Feb. 1893.) The influence of the fold is felt far for- 

 ward and there is other evidence of the unity in structure of the 

 whole belt of cortex thus folded. In rodents the folds are enor- 

 mously exaggerated and carried beneath the callosum, but it is 

 still morphologically the caudal margin — that part which lies 

 next the tela — which is thus modified. 



Inspection of Fig. 5 of Plate V. will show that in Phryno- 

 sofiia the evidence for our position is quite conclusive. In that 

 genus there is a distinct fornix commissure. It is about half 

 way between the callosum and the supracommissureand contains 

 a number of fibers, being nearly as large as either of the others 

 mentioned. These fibers are associated with the fornix columns 

 which pass forward in Edinger's Fornix-leiste and describe the 

 ventro-caudal curvature. Both sorts of fibers pass 'caudad and 

 spread out in the entire caudal cap of cortex. (Fig. 6, Plate V.) 



Meyer, ^ writing without knowledge of the writer's paper, 

 in 1892, makes very much the same distinctions between the 

 small-celled (facia dentata) and large celled lateral portion. He 

 is convinced that there are no connections with the olfactory 

 tract. Meyer identifies the mesal wall cephalad with the sep- 



'Ueber das Vorderhirn einiger Reptilien. Zeitsch. wiss Zool. VI. I, Nov. 1892 



