Literary Notices. xxix 



no reason to complain, for the hippocampal commissure itself is 

 " merely a part of the anterior commissure, which has been separated 

 off earlier in the phylogeny." In the placental mammal the anterior 

 part of the hippocampns is represented by the gyrus supracallosus 

 with the indusium. We are glad to note that especial emphasis is laid 

 on the fact that the fasia dentata is essentially supracallosal. We wish 

 to deprecate the writer's tendency to confuse superficial structures 

 (gyres) with internal elements (tracts) which, even when they become 

 substantially coextensive, stand in the relation of form and substance. 

 The same writer has recently contributed a paper to the Anatom- 

 ischer Anzeiger^ on the connection between the olfactory bulb and 

 the hippocampus in which he combats the idea that the external radix 

 of the olfactory reaches the hippocampus, as was stated by Edinger. 

 "The fibres of the external olfactory tract arise as axis cylinder pro- 

 cesses of the 'mitral cells' of the olfactory and terminate by means of 

 collaterals and end branchings in relation with the protoplasmic 

 processes of the cells of the pyriform lobe and olfactory tract." The 

 evidence is apparently conclusive that part of these fibres do so end; 

 indeed it has been recognized by the writer. In the fishes the tract 

 enters the homologue of the pyriform ; the question being whether 

 some of the fibres do not continue into the hippocampus, as they cer- 

 tainly seem to do in the lower forms. In Ornithorhynchus the intraven- 

 tricular lobe, or precommissural area, together with the lamina and the 

 quadrilateral area, form an intermediary station between the olfactory 

 lobe and the hippocampus. The axis cylinder processes of some of 

 these cells pass dorsad and may extend in the alveus to the extremity 

 of the hippocampus. Others enter the fimbria and still others cross 

 in the hippocampal commissure. Above these fibres, in the intra- 

 ventricular lobe is a compact bundle of fibres which enter the fasia 

 dentata and fimbria. In placental mammals it is probable that this 

 olfactory bundle of the fasia dentata runs in the striae Lancisii. 



c. L. H. 



The Brain of Desniognatlius.^ 



Though the morphological importance of the amphibian brain has 

 long been recognized by reason of the critical taxonomic position 

 occupied by the group, yet, aside from matters of external form, most 



^Anat. Anz., X, 15. 



'Fish, Pierre A. The Central Nervous System of Desmognathus fusca. 

 Jour. Morpk., X, i, 1895. 



