100 



years since. It is disappointing to find the old obviously untrue 

 theories persisted in universally in our own country and also generally 

 on the Continent. It is to be hoped that an advance will shortly be 

 made, and the real method acknowledged. 



Conclusions. 



1. The sulcus " interparietalis " of animals lower than anthro- 

 poids is identical with the sulcus postcentralis of man and should be 

 called by that name. 



2. The so-called sulcus postcentralis superior of pithecidae lies 

 within the sensory area and cannot therefore really be " post centralis " 

 in function. It should be called sulcus prae-parietalis as a distin- 

 guishing mark. 



3. The sulcus postcentralis superior of man is a composite sulcus 

 and consists of three separate parts, not all of which can be identified 

 in any given case. 



4. The sulcus cinguli has an arcus cinguli (mihi) thrown round 

 its outer end. Every deep sulcus is thus bounded by an arcus (e. g. 

 parieto-occipital, calcarine). 



5. The arcus cinguli is bounded by a sulcus to which I have given 

 the name of sulcus paracinguli. This sulcus is frequently continuous 

 with the sulcus postcentralis superior. To this fact is largely due the 

 variety of form which the latter sulcus displays. 



6. It is advisable to distinguish limiting sulci as being of the first 

 and second degree, according as they separate areas of totally different 

 function and structure, or merely specialised parts of one great area 

 from one another (e. g. the parietal area). 



Material. 



These facts were brought to light during the examination of 

 80 hemispheres, male and female, of all ages, with another — though 

 allied — end in view (1). 



I wish to thank Professor Elliot Smith, in whose department 

 of Anatomy this work was carried out, for the large amount of material 

 which he placed at my disposal, and also for the advice which he was 

 always so ready to give me. 



