214 MISS K. F. LANDKR ON THE 



The ^'' pseudo-Sylvian " fissure extends on the lateral aspect for 

 a distance of 30 mm. It is 16 mm. deep on the infero-lateral 

 margin and conceals a good deal of operculated cortex marked by 

 hidden perpendicular sulci, convei'ging towards a central point 

 near the highest part of the fissure. 8 mm. and 15 mm. from its 

 upper extremity the fissure gives off small branches which run 

 backwards and forwards respectively. 



The two terminal sulci are deep and well-marked. The 

 anterior one commences on the infei'ior aspect of the frontal pole 

 and runs downwards and backwards for 15 mm. and then turns 

 backwards to pursue a course parallel with the rhinal fissure. It 

 is 5 mm. deep. The posterior terminal sulcus is only 15 mm. long. 

 Between these and the rhinal fissure is a gyrus of 5 mm. breadth. 



The notch on the rhinal fissure, said to repi'esent the feline 

 " p.seu do Sylvian," lies 6 mm. behind the confluence of the 

 anterior and posterior terminal sulci and is 10 mm. long. 



There is a typical Ungulate sup7'as7/lvian arch, 16 mm. deep, 

 with a horizontal ramus 30 mm. long and vertical rami 13 mm. 

 in length. The gyrus suri^ounding the " Sylvian " fissure is in 

 most places over 12 mm. in width, but the termination of the 

 fissure reduces it to 5 mm. 



The posterior branch runs back to the occipital pole. It is 

 prolonged forwards beyond the posterioi- vertical limb of the 

 suprasylvian, reaching to within 5 mm. of the " Sylvian " fissure. 

 A shallow groove passes over the intervening gyrus, connecting 

 the two sulci. 



The sulcus ohliquus of Holl is represented by a triradiate sulcus 

 of which one branch runs forwards 15 mm. above the rhinal 

 fissure to a distance of 7 mm. from the -'Sylvian"; another 

 upwards to 7 mm. from the posterior branch of the suprasylvian ; 

 while the third passes backwards and downwards to a point 

 5 mm. from the hind end of the rhinal on the inferior aspect. 

 Also belonging to this complex is a small isolated sulcus, 7 mm. 

 long, lying between the anterior ramus of the triradiate and the 

 forward prolongation of the posteiior branch of the suprasylvian. 



A small curved sulcus j^i^^Tj^&ndicidar is, 8 mm. long, lies between 

 the "Sylvian" and suprasylvian. 



The diagonal sulcus is 22 mm. long and lies in the usual 

 position round the end of the anterior vertical limb of the 

 suprasylvian sulcus. Its extremities both curve upwards. A 

 gyrus of 4 mm. width separates the two sulci. Its accessory 

 sulcus appears to be absent. 



The orbital sulcus commences on the upper aspect of the frontal 

 pole, 7 mm. from the supero-mesial margin. It first forms a 

 curve, convex laterally, and then turns over the anterior margin 

 and runs backwards to join the anterior terminal sulcus at its 

 angle. The curved part is wide, but rather shallow, presenting 

 a trench-like appearaiace ; the hinder part is 10 mm. deep. A 

 short cross-branch connects it with the front end of the rhinal. 



From the junction of the anterior vertical and horizontal limbs 

 of the suprasylvian a well-marked tyxmsverse Jissure runs straight 



