Edward Anthony Spitzka 41 
RigHt HEMICEREBRUM. 
THe INTERLOBAR FissurEsS.—T7he Sylvian Fissure and its Rani.—The 
sylvian fissure is 4.3 em. in length and is deeper cephalad than on the left 
side: Presylvian depth, 14 mm.; medisylvian depth, 19 mm.; postsylvian 
depth, 23 mm. 
Its course is angular but generally approaches the horizontal. The 
basisylvian, measuring from the temporal tip, is 20 mm. in depth. The 
presylvian is bifureated, the longer limb attaining a length of 15 mm. 
The subsylvian is simple and 20 mm. long. The episylvian is unusually 
long (32 mm.) and sends a caudal ramus into the marginal gyre. The 
hyposylvian is merely indicated by a slight notch. 
The Central Fissure—tThe central fissure is 10 em. in length. As on the 
left half, the dorsal third of the fissure is quite straight and perpendicu- 
lar to the intercerebral cleft. At 3 em. from the dorsi-mesal margin, the 
fissure is interrupted by a hard, probably tubercular growth, adherent 
to the adjacent walls of the central gyres, indicated in Figures 5 and 3 by 
a dotted area. Cephalad the fissure anastomoses with the long limb of 
the supercentral over a vadum. The dorsal end is barely visible on the 
meson. The ventral end is separated from the sylvian by a slightly de- 
pressed isthmus. 
Occipital Fissure—The occipital fissure attains a mesial length of 3.5 
em., a dorsal length of 2.5 em. The fissure is of fairly uniform depth, 
and while exhibiting several interdigitating subgyres, shows no definite 
cuneo-quadrate subisthmuses. On the meson the fissure sends a ramus 
into the precuneus. Dorsally, just at the dorsi-mesal border, there is an 
appearance of trifurcation, owing to the presence of two adjacent fissural 
elements which run into the occipital cleft cephalad and caudad (Figure 
3). Closer investigation shows the deep occipital to continue laterad be- 
tween these two pieces, and end in a simple manner in the paroccipital 
gyre. 
The Calcarine Fissure-——The main stem of the calcarine is 2.1 cm. in 
length, and bifureates caudad, the dorsal limb joining the postcalcarine 
over a slight vadum (“ transcalearine isthmus”). The postcalcarine is 
4 cm. long and extends well upon the lateral surface. The straight course 
of the combined calearine and postealearine fissures, noted in other 
Eskimo hemicerebra, is quite marked in this case. 
The occipito-calearine fissural stem is 3.5 em. in length, and is deeply 
confluent with both the occipital and calearine. Its cephalic end ap- 
proaches the hippocampal fissure very closely. 
FISSURES OF THE FRONTAL LOBE (LATERAL SURFACE).—The Precentral Pis- 
sural Compler.—The supercentral is of zygal shape, and is confluent with 
the superfrontal. Its ventral limb is long and anastomoses with the cen- 
tral, but is separated from the precentral by an isthmus (Figure 5). The 
precentral is also of zygal type; its ventro-cephalic ramus is confluent 
with the sylvian by means of the well-marked diagonal. The transpre- 
central is an independent fissure. 
The superfrontal and medifrontal fissures are difficult to trace in defi- 
nite courses, particularly in the prefrontal region. The marked tendency 
