NERVOUS SYSTEM. VERTEBRATA. 



305 



lateral, and coronal, become broken up and supplemented 

 by irregular and unstable sulci in other large Ungulates, 

 it becomes a matter of the greatest difficulty to even recog- 

 nise these chief sulci in the Elephant's brain. There can 

 be little doubt as to the identity of the postsylvian sulcus, 

 which is so obliquely placed as to be almost horizontal 

 (fig. 174). This is in marked contrast to the observations 



Fir. 176. 



SULC-FARAORB. 



of Krueg on the Asiatic Elephant, and Flatau and Jacob- 

 sohn on the African Elephant, in both of which this sulcus 

 is represented as vertical. 



The sulcus below and parallel to it is probably the post- 

 lateral sulcus (fig. 174). 



The suprasylvian sulcus proper is broken up and rendered 

 complex by numerous branches, some of which seem (but 

 probably do not actually do so) to join the " Sylvian 

 fissure." The coronal sulcus is probably the deep, almost 



VOL. ii. x 



