Fish, Brain of the Fur Seal. 71 



off from the branch of the supersylvian, and then continuing to 

 the lateral fissure where a slight spur pointing toward the inter- 

 cerebral cleft might indicate its separation from the lateral. 

 Owen in his figure of the hemicerebrum of PJioca represents a 

 corresponding fissure as the coronal. 



Mesal Aspect. There is a slight appearance of the callosal 

 fissure in the splenial half of the callosum, but none at all for 

 the remaining half 



The hippocampal fissure is well developed and needs no 

 special comment. 



The splenial fissure is well developed and in general is as 

 described for Callorhmus, except that its position is farther re- 

 moved from the frontal portion of the cerebrum and that its 

 cephalic end cuts the margin and is shown upon the dorsal sur- 

 face. The postsplenial has about the same relations as in Callor- 

 hinus. 



The fissura sublimica of KiikenthaP is poorly represented 

 in my specimen of PJioca and is somewhat confused with smaller 

 branches and secondary fissures. It lies between the splenial 

 and the callosum. Kiikenthal finds this fissure also present in 

 Phoca groe7ilandica, PJwca barbata, Macrorhmus leonimis and 

 Otaria jiibata. In Callorhimis there was no appearance of this 

 fissure whatever. The fissura sublimica anterior of the same 

 author is more clearly represented. In my former paper, on 

 account of its position dorsal to the callosum, I designated it 

 questioningly as the supercallosal. On the left hemicerebrum 

 it is well developed and connects with the cruciate. On the 

 right side, however, the fissure is independent and much smaller. 

 In addition to this fissure, on each hemicerebrum, there is an- 

 other dorsal to it and in front of the splenial. In Callorhimis 

 I have called it the presplenial. 



The marginal or supersplenial is well shown in PJwca as in 

 Callorhinus but lies nearer to the dorso-caudal margin, approxi- 

 mately parallel with the splenial. In the intervening gyre there 

 are a few secondary fissures. 



^ Untersuchungen an Walthieren, 1S89. 



