NERVOUS SYSTEM. VERTEBRATA. 283 



D. 365. A brain labelled Indian Bear probably Ursus labiatus. 

 This is a small and comparatively simple Bear's brain; 

 but it presents features of peculiar interest, which enable 

 us to understand the arrangement of the sulci in the Seal's 

 brain. The anterior limb of the third arcuate gyrus has 

 grown backward in an operculum-like formation so as to 

 overlap a considerable portion of the second arcuate gyrus, 

 so that the " Sylvian fissure " and the suprasylvian sulcus 



Fig. 158. (x.) 



SULC.SUPRAS., SUBMERGED 2* GY' 



.SULC.COR. 



SULC.P.lAT.-J 



SULC.P. SYL.-" 



Fig. 159. (x.) 



, ,_ . ...SULC.COR. 



SULC.P. LAT.~ --j 



5YL.F 



(the anterior limb of the suprasylvian arc) appear to 

 become confluent. The operculum of the third gyrus has 

 been removed on the right hemisphere (fig. 158). Fig. 

 159 shows the appearance of the Sylvian region before the 

 dissection was made. 



Similar phenomena occur in the Badger (Meles, vide 

 supra) and in the Seals (vide infra) . 



There is a sulcus analogous to that distinguished by the 

 letter x in the Lion's brain. 0. C. 1325 TC. 



