clxxvi Journal of Comparative Neurology. 



denies that the latter is homologous with a convolution. [See else- 

 where in this number.] He also rejects the interpretation of Zucker- 

 Kandl, and "fails to see any indication of the return of the fascia 

 dentata to the under side of the splenium in order that it may round 

 the splenium and sweep forward in the nervus Lancisii in the manner 

 required by the theory." 



He emphatically states that the fascia dentata does not shade into 

 the cortex. Evidently some arbitrary criterion is used for the cortex 

 and the present writer is quite unable to agree with the statement of 

 fact. 



The original parts of the paper are devoted to a description of the 

 hippocampus of Hyperoodon, Phocsena, Monodon and Phoca. The 

 very valuable studies are summarized as follows : 



1. The fascia dentata is absent from the brains of Hyperoodon 

 rostratus and Monodon monoceras. It is but slightly developed in 

 PhoccBna communis and is small in Phoca vitulina. 



2. The extension of the fascia dentata in the several members 

 of the mammalian class varies as the relative development of their 

 olfactory apparatus. 



3. The column of large cells known as the nucleus fascise den- 

 tatse is the extreme margin of the general cortex. 



4. The granular and molecular layers of the fascia dentata be- 

 long to a separate portion of the wall of the fore-brain which has 

 undergone this characteristic development. 



5. In osmatic brains the fascia dentata ends in the mesal surface 

 of the brain, slightly in front of the anterior end of the ventricular 

 slit. Towards its anterior extremity its mesal and external portions 

 meet below at an acute angle. At its extreme anterior end the two 

 limbs of the V are opened out into a flat band which lies on the 

 surface. 



6. At its posterior or upper end the fascia dentata terminates 

 abruptly. It is therefore a long riband, folded into a trough ; if laid 

 out flat, the riband would be found to have a nearly uniform width 

 and a very regular and uniform structure. 



7. The stratum granulosum contains granules and small pyra- 

 mids (in about the ratio of 8 to i in the ox.) 



8. The anterior commissure and fornix vary in thickness with 

 the development of the rhinencephalon. 



9. There is no reason for associating the fascia dentata with the 

 striae Lancisii, gyrus supracallosis, and gyrus geniculatus, or for sup- 

 posing that these four structures belong to a single organ which forms 



