254 STUDY OF BRAINS OF SIX EMINENT SCIENTISTS AND SCHOLARS. 



Orbital Surface. — This surface is rather more complex in appearance than that 

 of the left half, due to the greater number of fissures and to their increased ramifica- 

 tion. It should be mentioned here that the mesorbital gyre is very narrow. 



Fissures of the Parietal and Occipital Lobes (Lateral Surface). The Post- 

 central Fissiiral Complex. — There is a triradiate postcentral piece whose dorsal rami 

 embrace the extremity of the caudal paracentral limb. The subcentral is the more 

 important element in the postcentral complex. Dorsad it is confluent with a segment 

 of the parietal, ventrad it dips into the episylvian, while its length is 4.5 cm. Li its 

 course it sends a ramus well across the postcentral gyre and caudad it joins the curved 

 intermedial. There is also a distinct transpostcentral. 



The parietal fissure presents unusual features. An isthmus near its middle breaks 

 up the fissure into two segments ; the cephalic one being confluent with the subcen- 

 tral, while the caudal one is independent and sends off two long rami, doi'si-cephalad 

 and ventro-caudad, respectively. A narrow isthmus separates it from the paxoccipital. 

 The paroccipital is of the usual zygal shape and anastomoses caudo-ventrad with one 

 of the exoccipital elements. The cephalic stipe is embraced between the occipital and 

 adoccipital. 



Two exoccipital elements can be made out on this half. Both are tri-radiate ; 

 the dorsal one is confluent with the paroccipital and with a cuneal fissure ; the ventral 

 one is independent. The latter is interesting because there is a decided opercular 

 formation of the part constituting the caudal wall of this fissure. It stands out quite 

 prominently and caps over a part of the fissure and the adjacent (depressed) gyres. 



In the subparietal area the fissuration is very intricate. The up-turned end of 

 the supertemporal joins the parietal over a vadum. There is a curved intei'medial 

 between the last-mentioned fissure and the episylvian, also joining the parietal. 



Mesial Surface. — The precuneal fissure is zygal and anastomoses with the 

 paracentral. Other segments help to make the precuneus of complex appearance. 

 The cuneus is also well supplied with fissures, there being three well-defined elements, 

 one of them joining the calcarine fissure. 



Gyres of the Parietal and Occipital lobes (Lateral Surface). — The post- 

 central gyre is very broad throughout. The parietal is large and complicated. The 

 paroccipital is of very good extent, and, similar to the same gyre on the left side, is 

 small in its cei)halic portion, but broad caudad of the occipital fissure. 



In the sub-parietal region, comprising the marginal, angular and post-parietal 

 gyres, we see the great breadth and massiveness as well as the regular complexity of 

 configuration so distinctive of this brain in tlie " posterior association area." Com- 

 pared with the left side it is not only more intricately fissured, but because of its some- 



