Fish, Cerebral Fissuration of the Seal. 



19 



PLATE II. 

 Reference Letters for the Fissures. 



ans. — ansate. ml. — medilateral. 



ant. — anterior. Post. — postica. 



Cal. — callosum P. Syl. — post-Sylvian. 



Con. — confinis. rh. — rhinal. 



Cor. — coronal. sc. — supercallosal (?) 



Cr. — cruciate. so.- — superorbital. 



Diag. — diagonal. spl. — splenial. 



/. — lunate. Sp. Syl. — super-Sylvian. 



lat. — lateral. Syl. — Sylvian. 



m. — marginal. 



EXPLANATION OF FIGURES. 



In all of the figures the important fissures are drawn with heavy lines and 

 the minor fissures with light ones. The first four figures were photographed 

 and enlarged drawings made. A small cross indicates a shallow depth of the 

 fissure at that point. The fissural names are based upon those used in the 

 Anatomical Technology (Wilder and Gage). 



Fig. I. Lateral view of the left hemicerebrum of the seal. 



Fig. 2. Mesal view of the right heraicrebrura . 



Fig. J. Lateral view of the right cerebrum. 



Fig. 4. Mesal view of the left hemicerebrum. 



Fig. J". The base of the seal's brain, after Tiedemann. This figure shows 

 the ventral outcropping of the vertical anterior (?) fissure in the cephalic wall 

 of the Sylvian. 



Fig. 6. The doisal aspect of the seal's brain, after Tiedemann. 



Fig. 7. Lateral aspect of the left hemicerebrum of the cat (diagrammatic). 



Fig. S. Mesal view of the cat's right hemicerebrum (diagrammatic). 



Fig. 9. Schematic type for brain of Carnivora, after Pausch. 



Fig. 10. A cross section of a fissure, to show the obliquity. 



Fig. II. A diagram to show the difference in the course of a fissure at its 

 surface and depth. The heavy lines represent the fissural walls at the surface. 

 The dotted lines and arrows represent the deep course of the fissure. 



