250 PHYSIOLOGICAL SERII-S. 



Civet and its near relations may be regarded as connecting 

 links between the typical Carnivora and the lowlier mam- 

 malian orders in which the crucial sulcus is absent and the 

 " Sylvian fissure " imperfect or wanting. 



The orbital (presylvian), corono-lateral, and suprasylvian 

 suk-i are simple and quite typical (figs. 122 & 123). The 

 Miprasylvian sulcus is the deepest sulcus in the hemisphere. 



Fig. 123. (Nat. size.) 



SULC. COR. LAT. 

 SULC.SUPRAS. / \. 



SULC.OR8. 



SYL.ECTOS- COMP. 



Fig. 124. (Nat. size.) 



SULC. INTER. SULC.CALC. 



A very deep calcarine is prolonged forward into the 

 intercalary sulcus which in turn joins the crucial sulcus 

 (fig. 124). The latin- in BO -mall (fig. 122), that it barely 

 reaches the dorsal surface. 



The genual sulcus is joined to the crucial sulcus on the 

 left hemisphere by a shallow furrow (fig. 124). 



The " feline Sylvian fissure " is so ill-defined that there 

 is a conflict of opinion as to which sulcus really represents 

 it. This further exemplifies the morphological instability 



