Herrick, Morpliology of Brain of Bony FisJics. 353 



Sylvian caudo-laterad, isolated fibres and small tracts pass 

 toward the periphery nearly in the plane of the section. The 

 peripheral or ventricular border of this lobe is clothed with a 

 single-layered epithelium, from the apices of the cells of 

 which fibres extend long distances entad, as in the brains 

 of Sauropsida. The cells of the lateral lobe (Plate XXV, 

 Fig. 6) are fusiform, with clear spherical nuclei of large 

 size. The protoplasm is faintly stained and the processes 

 are short. The cells are similar to those found in jesthesodic 

 areas of the cortex in reptiles. 



The cuneus consists of concentric layers of smaller fusi- 

 form cells. Near the surface, however, is a small zone of 

 cells like those of the lateral lobe, or nearly twice the size 

 of those composing the bulk of the lobe. Dorsad this lobe 

 borders upon the occipital, and caudad it is separated from 

 the temporal and hippocampal. 



The occipital lobe merges insensibly into the temporal ventro- 

 laterad, but extends cephalad a long distance upon the dorsal 

 aspect. In the present region it is difficult to say which is cut. 



The mcsaxial lobe occupies the whole mesal aspect, and is 

 divided into a cephalic and caudal portion by a fissure in the 

 mesal surface. This may be the homologue of a fissure men- 

 tion by C. Judson Herrick in the cat-fish. 



The cellular elements are small and vary considerably. 

 Cephalad of the above fissure, which may be called splenial 

 for convenience, and caudad of the callosal tracts, is an area 

 where numerous small fusiform cells are closely massed. 

 Caudad of the splenial is a region where there is a mixture 

 of the above described and narrow deeply stained pyramidal 

 cells resembling the so-called rhinomorphic cells. A similar 

 sort of cells occupies the tract caudad of the peduncles in the 

 central lobe (Fig. 4, Plate XXV). Cephalo-mesad of the 

 pyramids at this level is a dense clustre of small fusiform 

 cells, with a slight admixture of pyramidal elements. A 

 section at the dorsal level of the callosum is figured in Plate 

 XXIV, Fig. 2, and requires no special description. 



