COETICAL CELL LAMINATION OF FAPIO HAMADRYAS. 619 



heunspliere but not in the left. Below it, in the temporal 

 lobe, lie one or two sliallow grooves {Tin. ^,.2, etc.), which may 

 be taken to represent the sulcus temporalis medius. 



The sulcus post-centralis superior (pc.5.) is a shallow 

 groove lying almost horizontally opposite the upturned 

 posterior end of the sulcus cinguli. 



The sulcus intra-parietalis (ijj.) starts anteriorly in 

 the space which is bounded above and in front by the sulcus 

 centralis, and below and behind by the Sylvian fissure, ft 

 runs at first upwards and backwards, then turning backwards, 

 disappears underneath the occipital operculum. Here it 

 bifurcates. Its outer branch runs outwards on the anterior 

 wall of the sulcus lunatus, and then divides into two rami, 

 of Avhich one runs to the bottom of that fissure while the 

 other runs upwards. The inner branch, by far the larger of 

 the two, is called the ramus parieto-occipi talis {I'j^o.) of 

 the sulcus intra-parietalis. It cuts very deeply through the 

 supero-mesial border of the hemisphere, then runs straight 

 downwards to end in a bifurcation, the branches of which lie 

 more or less parallel to the sulcus calcarinus. 



Owing to the extent of the occipital operculum, this ramus 

 parieto-occipitalis appears to be a mesial continuation of 

 the sulcus lunatus; in reality the two fissures are partially 

 separated by a submerged gyrus lying near the supero-mesial 

 border. 



The fissura parieto-occipitalis {fpo.) is a triradiate 

 fissure, the two posterior rays of which arch round the 

 anterior limb of the terminal bifurcation of the parieto- 

 occipital branch of the sulcus intra-parietalis. These two 

 rays are better developed in the left hemisphere than in the 

 right, and there the lower one forms a superficial connection 

 with the posterior limb of rpo. The anterior ray is poorly 

 developed. 



The sulcus subparietalis [sp.) (posterior limbic sulcus) 

 lies between the fissura parieto-occipitalis {fpo.) and the 

 sulcus cinguli. The main portion of this fissure runs upwards 

 and slightly backwards; its lower end is divided into two 



