Fish, Brain of the Fur Seal. y$ 



ZALOPHUS CALIFORNIANUS. 



Through the kind permission of Professor Wilder I was 

 permitted to remove the brain from this young sea Hon. Its 

 mother came originally from the Pacific coast and the present 

 specimen was found dead in the cage with her while in transit 

 to the East and was presumably not far from " term." It meas- 

 ured 43 centimeters long and has been in the Cornell museum 

 of Vertebrate Zoology for some years. 



The brain was in a fairly good state of preservation and 

 was photographed soon after its removal. It was too delicate 

 to permit of much manipulation and some of the fissures were 

 not sounded as thoroughly as in the other specimens. The cere- 

 brum of this specimen does not show the same degree of com- 

 plexity relative to the fissuration as indicated by Murie^ in Otarm 

 jiibata. A direct comparison of the fissures, however, is not easy 

 as the latter author attempts to homologize them with those 

 of the human cerebrum. 



The olfactory apparatus is well developed. Not as largely 

 as in the bear, however, but greater than either of the seals. The 

 rhinal fissure, as in the other forms, is well marked and passes 

 caudad into the mouth of the Sylvian fissure. The postrhinal 

 is formed from the subfissure (postica ?) and has no connection 

 whatever with either the rhinal or Sylvian. 



Lateral Aspect. The Sylvian is prominent and occupies its 

 usual position. In its caudal wall is a subfissure (postica?) and 

 subgyre which as in CallorJiimis is continuous on the ventral 

 aspect with the pyriform or temporal lobe. 



The supersylvian with its cephalic and caudal portions, the 

 pre- and postsupersylvian, is more nearly in accord with the 

 condition found in the bear than in either of the seals. It rep- 

 resents an intermediate condition between the two. The pre- 

 supersylvian lies very close to the Sylvian but does not actually 

 enter it as in the seals. Its average distance from it is about 4 

 millimeters ; while the distance from the Sylvian to the post- 



' 1874. Transactions of the Zoological Society of London. 



