56 C. W. M. Poynter 



sulcus diagonalis is not connected with tlie latter. The ramus 

 posterior ascendens is without anastomoses and terminates by 

 bifurcation. The sulcus centralis is s}Ti\metrical with the left; 

 a superficial furrow connects it with tlie sulcus retrocentralis 

 inferior. Confluence with the fissura Sylvii through the sulcus 

 subccntraiis anterior which is well developed, is prevented by a 

 narrow bridging convolution. 



Frontal Region 



This region sliows tlie same high development of the convolu- 

 tions as found on tlie left side. 



The sulcus f'raecentralis inferior begins ii mm. above the fis- 

 sura Sylvii and extends upward for the normal distance where it 

 becomes continuous without interruption with tlie sulcus prae- 

 centralis superior. Xo ramus horizontalis can be discovered. 



Tlie sulcus f'raecentralis superior is more nearly parallel to the 

 central fissure than tlie inferior praecentral sulcus ; it terminates 

 well on the supero-lateral surface of the hemisphere, or almost 

 immediately after its junction witli the sulcus frontalis superior. 

 The superior frontal g>Tus, as on the left, is well developed, and 

 presents several short furrows on its surface, which are the 

 representatives of the sulcus frontalis mesialis. 



Tlie sulcus frontalis superior appears as a deep posterior seg- 

 ment which is connected with the sulcus praecentralis superior, 

 and an independent less important anterior ramus. Sulcus fron- 

 talis medius is an unimportant short segment connected with the 

 posterior ramus of the sulcus frontalis superior. 



5"«/t^M.y frontalis inferior is ver}" s^^llmetrical with the left in 

 position and shape. It however has more connections, in addi- 

 tion to the anastomosis, with the fissura SylWi through the sulcus 

 diagonalis. It anastomoses at its anterior end with the sulcus radi- 

 atus (Eberstaller'^, which is well developed, and with a segment 

 of sulcus fronto-marginalis. There is. beside the short inferior 

 segment in connection with the inferior frontal fissure, a larger 

 segment more superiorly placed along the frontal margin: these 

 two segments are the representatives of the sulcus fronto- 

 marginalis. 



400 



