6o C. W. M. Poynter 



The sulcus fronto-marginaUs is present as three separate seg- 

 ments, the inferior one being superficially connected to the Syl- 

 vian fossa. 



The Parieto-Occipital Region 



This region also gives the appearance of poor development, the 

 convolutions are flat and the fissures narrow, although of normal 

 depth. The surface seems to be relatively less than that of the 

 frontal region due to the shape of the brain. That can be best 

 understood from the cut of the dorsal surface. 



The interparietal complex in superficial arrangement is like type 

 I of the text ; but due to an annectant which almost separates 

 the inferior and superior retrocentral fissures, and due to the 

 fact that an antero-descending branch of the interparietal 

 is really the continuation of that sulcus, the arrangement 

 really falls in type V, a much rarer condition. The sulcus retro- 

 centralis inferior is directly confluent with the fissura Sylvii. Just 

 in front of it is a sulcus running parallel to it and also communi- 

 cating with the fissura Sylvii. This fissure is divided into two 

 parts by a deep annectant, and probably represents a sulcus sub- 

 centralis posterior joined to one of the accessory furrows which 

 are occasionally encountered on the retrocentral gyrus rather than 

 a secondary inferior retrocentral sulcus. 



The sulcus inter parietalis is present as a continuous sulcus con- 

 nected to the sulcus occipitalis transversus. It is confluent 

 through a lateral branch with the superior temporal and directly 

 with the sulcus parietalis. The sulcus transz'crsus presents no 

 points of interest except a confluence with the sulcus temporalis 

 superior and the incisura parieto-occipitalis. The sulcus occipi- 

 talis inferior is well developed and confluent with the sulcus tempo- 

 ralis medius. The sulcus occipitalis superior is present as a short 

 segment which is connected with one of the two segments of a 

 sulcus lunatus. The sulcus temporalis superior is very irregular in 

 its development, it may be described as four segments. The ramus 

 anterior is independent of the rest of the sulcus but cuts deeply 

 through the superior temporal gyrus to connect with the fissura 

 Sylvii. The ramus medius is the most important portion of the 

 fissure. It begins well down on the temporal pole and passing up 



404 



