580 ON A COMPLETE DEBOUCHEMENT OF THE SULCUS ROLANDO. 



Having examined carefully more brains of men belonging to the 

 dark races, I may also state that junctions of the Sulcus Rolando 

 with the other Sulci, are not uncommon and, very likely, occur 

 more frequently than in the brain of men of our race. 



Explanation of Plate 18. 



Fig. 1, A. — Part of the right hemisphere of the Cerebrum of the Australian 

 Aboriginal, showing a complete junction of the Sulcus Rolando 

 (R.), with the horizontal ramus of the Fiss Sylvii (S.) 

 B. — Corresponding part of tbe left hemisphere of the same brain, 

 showing a junction of the Sulcus Rolando (R.) with the Sulcus 

 prcecentralis (P.) 



Fig. 2, A. — Part of the right hemisphere of the brain of another Australian 

 Aboriginal, showing also a complete debouchement of the Sulcus 

 Rolando into the Fiss. Sylvii (S.) 

 B. — Corresponding part of the left hemisphere of the same brain. 



The same lettering in all the figures. 



R. — Sulcus Rolando. 



S. — Fissura Sylvii. 



S'. — Ramus ascendens Fiss. Sylvii. 



T. — Sulcus Interparietalis. 



F, — Sulcus frontalis, Imp. 



P. — Fiss. Prcecentralis. 



T. — Sulcus Temporo Sphenoidalis primus. 



