248 STUDY OF BRAINS OF SIX EMINENT SCIENTISTS AND SCHOLARS. 



Orbital Surface. — Two fissural segments mark the orbital surface, each of 

 zygal shape. The larger caudal one has a transverse zygon or stem, with two long 

 cephalic raini embracing the smaller segment. The olfactory fissure is about 4 cm. in 

 length and anastomoses with the subrostral, as described above. 



Gyres of the Frontal Lobe (Lateral Surface). — The precentral gyre is mas- 

 sive and complex. The superfrontal is of usual size, but tends to partial subdivision 

 in a longitudinal manner, owing to the paramesial fissural segments. The medifrontal 

 gyre is notably extensive, and intricately fissured, particularly by transverse pieces. 

 The subfrontal area is not of the common form, but seems rather made up of three 

 convolutions separated by transverse fissures (one of these being the radiate). These 

 fissures are very deep, and the cortical expanse in this area is doubtlessly greater than 

 in average brains. 



Mesial Surface. — The marked fissuration of the superfrontal gyre on the mesal 

 surface by means of the long, tortuous and much-ramified frontomarginal fissure gives 

 it a complex appearance. The paracentral gyre is rather small. The frontal portion 

 of the callosal gyre is simple. 



Orbital Surface. — The mesorbital gyre is narrow. The remainder of this sur- 

 face may be said to be divided into a preorbital and a postorbital region by the larger 

 of the two zygal orbital fissures. The preorbital region consists of a V-shaped gyre 

 embracing a quadrate area within the cephalic arms of the smaller orbital fissures. 

 The postorbital region is of a simple conformation, indented by an orbital limb of the 

 basisylvian cleft. Mesad and laterad of the larger orbital fissure there are gyral 

 portions of fair size. 



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

 central Fissural Comiplex. — The dorsal postcentral segment is readily identified. It is 

 4 cm. in length, anastomoses superficially with the caudal limb of the paracentral but 

 is otherwise independent. In seeking out the representation of the subcentral we 

 meet with such exceedingly intricate foldings in the region comprising the ventral 

 portion of the postcentral gyre and the marginal gyre that it is difficult to determine 

 the exact interpretation of all the features presented here. The irregular tri-radiate 

 fissure, whose limbs anastomose, cephalad with the central and caudad with the pari- 

 etal, while doubtlessly the subcentral is certainly of unusual appearance. Between 

 its ventral ramus and the end of the central lies the Y-shaped transpostcentral, dip 

 ping into the sylvian cleft. 



The fissure lying dorsad of the subcentral and for the greater part of its course 

 running parallel with the dorsal limbs of the subcentral is the parietal. The peculiar 

 arrangement of the fissures in this region requires particular attention. At a point 



