62 Journal of Comparative Neurology. 



Lateral Aspect. The Sylvian is a convenient fissure to be- 

 gin with. There is usually some evidence of it if the brain is 

 at all fissured, and in the lower animals, at least, it forms a cen- 

 ter around which other fissures are more or less regularly ar- 

 ranged. In Callorhmus the Sylvian extends in a dorso-caudal 

 direction, inclining somewhat toward the vertical. Apparently 

 it terminates in a fork, but when the walls of the fissure are di- 

 varicated it is seen that the cephalic or anterior branch is really 

 another fissure, which, after its superficial union with the Syl- 

 vian, becomes a submerged fissure lying just beneath the surface 

 of its cephalic wall and running parallel with it to the base 

 of the brain, but not actually connecting either with the Sylvian 

 or with the rhinal. The Sylvian on account of the subfissural 

 complication appears to be a larger fissure than it really is. 



In a former paper ^ attention was called to the fact that this 

 vertical fissure (superficial vertical branch of the Sylvian) had 

 been mistaken for the true Sylvian. Both fissures are well 

 marked and cannot be ignored, but it is an unusual circumstance 

 for the Sylvian to assume a strictly vertical position in the adult 

 and there would, moreover, remain a fissure in the usual situa- 

 tion of the Sylvian unaccounted for. In my former paper I des- 

 ignated this vertical fissure as the Anterior of the Felidae, and 

 found at a later date, while consulting Krueg's article ^ that 

 he questioningly represents a similar fissure by the same name 

 in CalocepJialus i^Phocci) vitiiliiius. CallorJiiiius, while showing 

 this fissure similarly situated, instead of elucidating the compli- 

 cations, seems rather to add to them and to suggest a probable 

 doubt as to the correctness of the homology with the anterior 

 fissure. Indeed, the conditions are strongly suggestive of its 

 being nothing more than the detached frontal portion of the 

 super-sylvian fissure. An examination of the brains of certain 

 bears tends to illuminate this view. In the family Ursidac as 



1 '96. P. A. Fish. A note on the Cerebral Fissuration of the Seal (Phoca 

 Vitulina). Jour. Comp. Neurol. VI, 15-19. 



■■•'So. J. Krueg. Ueber die Furchen auf der Grosshirnrinde der zonopla- 

 centalen Silugethiere. Zeit. f. wiss. Zoologie, XXXIII, 595-672, 5 plates. 



