STUDY OF BKAIXS OF SIX EMINENT SCIENTISTS AND SCHOLARS. 253 



length, measured with a wet string, is 7.5 cm. The radiate, 3.5 cm. in length, anas- 

 tomoses with the subsylvian, the subfrontal, and superficially with the orbitofrontal. 



Mesial Surface. — The supercallosal, measured from its junction with the para- 

 central, is 12.5 cm. in length. It sends off a number of rami, several of which join 

 frontomarginal segments in the superfrontal gyre. The paracentral is a moderately 

 sinuous fissure ; its caudal limb passes verticallj^, while the cephalic limb is barely 

 indicated by a slight notch. There is an intraparacentral piece of z3'gal shape whose 

 course is parallel to the main fissure, and whose cephalic rami lie in the ideal pro- 

 longation of the cephalic limb bounding the paracentral gyre. Dorsad of this, across 

 the dorsi-mesal margin lies a tri-radiate piece which may represent the inflected (not 

 unlike that seen in the brain of the Eskimo " Nooktah," right hemicerebrum ; see the 

 writer's paper, 1902). 



There are two medicallosal segments in the callosal gyre ; a long one (4.5 cm.) 

 lying dorsad of the callosum, a shorter one cephalad of the genu. 



The rostral fissure is 5 cm. in length, while an irregular subrostral passes over the 

 margin to lie cephalad of the olfactory fissure. 



Orbital Surface. — The arrangement of the orbital fissures resembles that of the 

 left half, but the transorbital segment is better marked. On the whole, the orbital 

 surface of this side is of a more complex appeai'ance. The olfactory fissure is 4.2 cm. 

 in length. 



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

 uniform breadth and of a good size. It is traversed by the central-supercentral anas- 

 tomosis and indented by short rami of the central and precentral. The superfrontal 

 is quite broad and distinctly demarcated. Six fissural segments, generally of trans- 

 verse direction mark its surface. The medifrontal is notable for its great breadth and 

 for its distinct division into two tiers. The transverse breadth of the medifrontal dis- 

 trict averages about 4 cm., a large dimension as compared with ordinary brains. The 

 subfrontal gyre is correspondingly reduced to a width of about 2.5 cm., and is in every 

 way smaller than its fellow on the left side. All the frontal gyres may be described 

 as well-developed and as particularly complex in the prefrontal region. 



Mesial Surface. — On the mesial surface the superfrontal gyre is of good uni- 

 form width, marked by several rami of the supercallosal and by a number of fronto- 

 marginal segments. The paracentral gyre is of rectangular shape, and taking the 

 cephalic limbs of the intraparacentral as representing the ideal continuation of the 

 abbreviated cephalic limb of the paracentral proper, the gyre has a length of 4 cm.; 

 somewhat greater than on the left side. The frontal portion of the callosal gyre ex- 

 hibits a tendency to subdivision by two medicallosal segments. 



