62 C. ir. M. Poyntcr 



retro-calcarine and calcarine fissures. The fissure terminates pos- 

 teriorly at the occipital pole in two widely branching sulci. Ante- 

 riorly the fissura calcarina terminates in the fissura hil^pocanipi. 

 This connection is not a superficial one, but the fissura calcarina 

 continues at almost its maximum depth into the fissura hippo- 

 campi. Both the superior and inferior limiting sulci are well de- 

 veloped. The siibcolcarinc group (Sergi) is very complex. The 

 fissura collatcralis is simple and extends well forward. It com- 

 municates with the sulcus temporalis inferior. The sulcus tem- 

 poralis inferior is well defined,. but in addition to the continence 

 just mentioned is connected with the middle temporal sulcus. 



RigJit IlonispJicrc: Lateral Surface 

 Fissura Syh'ii presents one anterior ramus which cuts deeply 

 into the dorsal operculum, but. due to the development of the 

 operculum below, the insula is not exposed. It branches at its 

 upper end into two short sulci. The ramus posterior ascendens is 

 slightly longer than the left and ends by bifurcation. The ramus 

 posterior descendens is not represented. 



The sulcus centralis is symmetrical with the left. The praecen- 

 tral g}rus is cut by two furrows instead of one as on the left. 

 The mesial furrow seems to be the posterior segment of the sulcus 

 frontalis medialis. and the lateral one is clearly the continuation 

 of the sulcus frontalis superior. Neither furrow cuts deeply into 

 the sulcus centralis. The sulcus praecentralis appears on the sur- 

 face to be a continuous fissure beginning in the fissura Sylvii and 

 extending to the mesial border of the hemisphere. But on sepa- 

 rating the lips of the sulcus it is seen to be made up of a sulcus 

 praecentralis superior and a sulcus praecentralis inferior by a bridg- 

 ing convolution which almost reaches the surface. Just below the 

 aiinectant is a horizontally directed branch, which is the ramus 

 horizontalis. 



The sulcus frontalis superior is a long fissure uninterrupted by 

 annectants. It has no true connections although it is superficially 

 connected with the sulcus praecentralis superior and the sulcus 

 medius. The sulcus frontalis nu\iius is represented by two seg- 

 ments connected superficially. 



406 



