Edward Anthony Spitzka 63 
alad with the collateral. It is deeply confluent with both the occipital 
and ealearine fissures. 
FISSURES OF THE FRONTAL LOBE (LATERAL SURFACE).—The Precentral Fis- 
sural Complea.—As may be seen in Figure 15, the supercentral is practi- 
eally identical with the one on the left side. Furthermore, there is a 
similar piece at the site of the precentral-medifrontal segment (Schafer— 
Quain’s “anterior precentral ramus’) which does not, however, anasto- 
mose with the central as happens on the left side. It is in this case an 
independent tri-radiate fissure. Ventrad is another precentral, of a zygal 
shape, with one of its limbs joining the diagonal-subfrontal junction. 
Throughout, there may be found not a little resemblance between the two 
sides (compare Figures 13 and 17). 
The diagonal dips deeply into the sylvian fovea, and, traversing the 
subfrontal gyre, as on the left side, to join the subfrontal as well as the 
precentral limb. The transprecentral is present, but does not appear on 
the convex surface. 
The superfrontal springs from the supercentral in a similar manner to 
that of the left, and may be traced as a continuous fissure to its jJunc- 
tion with the orbito-frontal. Unlike its fellow on the opposite side, this 
superfrontal fissure sweeps further laterad in the prefrontal region, and 
comes to occupy a position corresponding to the cephalic medifrontal 
piece of the left hemicerebrum. This divergence renders the superfrontal 
gyre broad and the medifrontal correspondingly narrow. The medi- 
frontal gyre is chiefly traversed by transverse segments. 
The subfrontal is a very tortuous fissure springing from the precentral- 
diagonal junction as described. Its total length is 3.5 em. The orbito- 
frontal is a short (2 em.) piece anastomosing with the superfrontal. 
MESIAL SURFACE.—The supercallosal is 7 em. in length, confluent with 
the paracentral and ending just cephalad of the genu. (N. B.—The inter- 
ruption of the fissure in Figure 18 is due to defect in the plate.) Several 
fissural segments lie in the course of the frontomarginal, of which two are 
distinct longitudinal pieces. The rostral is 4.5 em. in length, while the 
subrostral is quite short and shallow. Between the rostral fissure and 
the genu lies a medicallosal piece which joins a “ transrostral”’ element, 
The paracentral fissure is almost the exact counterpart of its fellow on 
the left side. 
ORBITAL SuRFACE.—The orbital fissure presents a well-marked trans- 
verse stem from which spring two long cephalic rami. Another tri- 
radiate piece joins the orbitofrontal. The olfactory is 4.8 em. in length 
and simple. 
GYRES OF THE FRonTAL Lone.—The precentral gyre is in general wider 
than its fellow on the left side. The superfrontal is also much broader, 
while the medifrontal is correspondingly less in width. Both of these 
gyres are well supplied with fissures tending in a transverse direction. 
The subfrontal gyre is much lTarger and better developed in all respects 
than the left, but like the latter is completely traversed by the diagonal. 
MestaL SurFAce.—On the meson, the superfrontal gyre is broader and 
more richly fissured than the left. The. region marked by the rostral 
