286 STUDY OF BRAINS OF SIX EMINENT SCIENTISTS AND SCHOLARS. 



seven alternate curves and in general the fissure on this side is more tortuous than the 

 one on the left, as will readily be appreciated by glancing at Figure 3. It sends a 

 well-marked ramus into each of the adjacent gyres. The fissure is of good depth 

 throughout, and independent of neighboring fissures. Its ventral end is separated 

 from the sylvian, and its dorsal end is visible on the mesial aspect for about 1.5 cm. 



The occipital Jiisicre, as on the left side, ascends to the dorsi-mesal margin at a more 

 obtuse angle than is common ; in this case it is 68° (on the left it is about 70°). Its 

 length on the mesial surface is 2.9 cm., on the dorsum 2 cm. As on the left half there 

 exists a submergence of the cephalic arm of the paroccipital gyre ; the cephalic stipe 

 therefore is likewise confluent with the occipital, but in this case at a greater depth. 



The calcarine fissure runs a very irregular zig-zag course, with numerous rami, and 

 terminates just at the pole. Somewhat caudad of this terminus there is a short 

 segment which corresponds with the piece on the left half presumed to be the post- 

 calcarine ("sulcus extremus" of Schwalbe). 



The calcarine and occipital fissures meet at nearly a right angle to continue as the 

 occipito-calcarine stem for a distance of 3.8 cm., and just as in the left half, almost 

 reaching the hippocampal fissure. 



Fissures of the Frontal Lobe (Lateral Surface). T//e Precentral Fissural 

 Complex. — In this case there are two segments, the supercentral and precentral. The 

 former is of zygal form with its dorso-cephalic ramus confluent with the superfrontal. 

 It is separated from the precentral by a superficial isthmus. The precentral is of good 

 length and sends a long ("anterior precentral") ramus nearly across the medifrontal 

 gyre, resembling its fellow on the left in this respect. Further ventrad springs another 

 ramus which joins the " anterior precentral " by an oblique anastomosing fissure ; in 

 this way a gyral islet is formed which lies a trifle bek)w the general surface of the 

 cerebrum. 



There is a short transprecentral, while the diagonal is absent. 



The superfrontal is quite tortuous and as on the left side, is interrupted at about 

 the cephalic third. The cephalic shorter segment is of zygal shape, but includes a 

 depressed gyral " islet " similar to the oije mentioned in the description of the j^re- 

 central. As for the remaining fissures of this surface it is exceedingly difficult to 

 recognize the typical pattern. While there are small scattered segments coiTespond- 

 ing to the courses of the medifrontal and subfrontal fissures it is hard to trace them 

 with any degree of certainty. The intricacy of the fissural arrangement here will best 

 be appreciated on studying Fig. 4. One fissure, however, is distinctly marked, namely, 

 the orbitofrontal. It is 3 cm. in length, and is joined by a piece which by its analogy 

 with the fissuration of most brains can safely be named a medifrontal segment. 



