288 PHYSIOLOGICAL SERIES. 



visible in the figures]. This undoubtedly represents the 

 paraoaloarine sulcus of the Bears (vide supra). This conjoint 

 entolateral-paracalc:irine sulcus is as much as 2 cm. <l.--j 

 in parts of its course. This may he partly due to the fact 

 that the paracaudal sulci of the Bear's brain are not pn - m 

 here. As in the Bear's brain, the posterior rhinal fissure 

 en. Is upon the ventral surface of the hemisphere, i. e. does 

 not extend backward on to tha mesial surface. Behind its 

 extremity we find in Otarian, well-developed representative 

 of the peculiar sulcus distinguished by the name " ursinus " 

 in the Bear. In fact this sulcus is oven larger than it is 

 in the Bear's brain, and extends upward on the lateral 

 iii r face between the postsylvian and postlateral sulci 

 (fig. 161). 



Fig. 163. (x|.) 



SULC.MARG. 



SULC .VERT 

 SULC.CRU. 



SULC.BISEC. ... 



SULC COLL. 



SULC.URS. 

 RHIN.f. 



The calcarine sulcus is very deep and its forward con- 

 tinuation (intercalary) is oblique and very short (fig. \(V.\). 

 There i- a deep retrocalcarine branch (SULC. P. CALC.) of the 

 ealrarine. Th-re is a small collateral sulcus, analogmi- 

 to but not strictly homologous with the human coll.i 

 (vide infra). 



There is a typically Ursine crucial sulcus (fig. 1(]'2) with 

 large j.recnu'ial branches, and consequently the " Ursine 

 i.i/M|M, " O f MJvart i- very large and distinct. 



Tho>e peculiar >ulei which were distinguished by the 

 names u vertical " and " bisector " in th<> Bear's brain are 

 in the same forms in this brain (fig-. 1U2 <fc 1(515) 



