82 Journal of Comparative Neurology. 



the usual dorso-caudal direction. Apparently some unusual 

 conditions exist here, which may perhaps be accounted for by 

 the nearly complete disappearance of the postica. 



The presupersylvian resembles the corresponding fissure 

 in PJioca regarding its extreme vertical position and apparent 

 union with the Sylvian for only the ventral third of its course. 

 It differs from PJioca in not being disconnected from the su- 

 persylvian. 



The supersylvian fissure resembles that of PJioca in extend- 

 ing a branch of good size to connect with the ansate. 



Posts upersylvian. In the two hemicerebrums of the male 

 there was a connection between the supersylvian and the post- 

 supersylvian much as in Phoca. In the hemicerebrums of the 

 female there was an entire disconnection of these fissures. 



The cruciate fissure more than in any of the others resem- 

 bled that of PJioca. It forms a good intermediate stage be- 

 tween CallorJiimis and PJioca. As with PJioca the fissure is rep- 

 resented on the mesal surface as much, if not more than upon 

 the dorsal. In the left hemicerebrums of both brains the cru- 

 ciate is apparently continuous with the splenial. Upon the 

 right hemicerebrums there is no such connection. 



Precruciate. In all four hemicerebrums the precruciate 

 extends over upon the mesal surface for some little distance. 

 It is more largely represented upon the dorsal surface and its 

 lateral end makes a very decided curve toward the coronal fis- 

 sure. There is almost a superficial connection between the 

 cruciate and the precruciate. The conditions in PJioca indicate 

 that such a connection has occurred even to the extent of their 

 almost complete mergence into eachother. 



" Ursine Lozenge." This area is, with the exception of 

 PJioca where it is undistinguishable, smaller than in any other 

 forms. It is nothing more than a narrow gyre, situated at a 

 slightly lower level than the adjacent gyres, suggesting a prob- 

 able preparation for the loss of its identity in PJioca. 



Postcruciate. In MonacJnis this fissure was the least satis- 

 factorily represented than in any of the other forms. In the 

 two hemicerebrums, it does not seem to be represented at all. 



