Edward Anthony Spitzka 43 
eral rami spring from the combined fissure, and it anastomoses with a 
segment of the parietal. There is no transpostcentral. 
The parietal is interrupted by a narrow isthmus not far from the paroc- 
cipital. In the parietal gyre are several fissures, the most cephalic one 
(see Figure 3) corresponding with Brissaud’s transparietal. 
The paroccipital is of very unusual form, owing to the overlapping of 
the cephalic portion of the paroccipital gyre by a parietal gyral oper- 
culum.2 The overlapping is considerable in extent, hiding from view 
both the cephalic ramus and stipe of the paroccipital. An independent 
preparoccipital fissure dips under this operculum,.as does a segment which 
runs parallel! with the parietal. The entire arrangement is very unusual 
indeed, and seems not without significance in its bearing upon the devel- 
opment of the paroccipital from the primate exoccipital. The caudal 
ramus is short; the caudal stipe long and tortuous and anastomosing with 
the occipital fissure. 
The intermedial fissure joins the supertemporal parietal and an un- 
named fissure in the angular gyre, confluent with the paroccipital. 
The exoccipital complex is intricate. There is a zygal, much-ramified 
exoccipital sezment whose caudal limbs embrace the lateral extremity of 
the postealearine; a cephalic limb anastomoses with a meditemporal seg- 
ment. 
MeEsIAL SuRFACE.—The precuneai fissure is of zygal shape, but the course 
of the stem is in an unusual direction, namely, dorso-ventrad instead of 
eaudo-cephalad. 
There is a tri-radiate intraprecuneal fissure which anastomoses with 
the paracentral. + 
The cuneus is richly fissured. 
GYRBS OF THE PARIETAL AND OCCIPITAL LOBES (LATERAL SURFACE).—The 
postcentral gyre is of more uniform width than the precentral, and is 
rendered quite flexuous by the indenting rami of the adjacent fissures. 
The parietal gyre, aside from the peculiar opercular formation by which 
it partially overlaps the paroccipital gyre, and while shorter than its 
fellow on the left side, is intricately convoluted. 
The paroccipital gyre is of a peculiar form. In the overlapped portion, 
as described before, there is a preparoccopital fissure, while two other 
fissures arise from the occipital cleft. - 
The marginal eyre, curving round the bifureated episylvian, is very 
broad. The angular and postparietal gyres present a very complex con- 
figuration, being broken up into several areas by numerous confluences 
of fissures. An imaginary line passing from the occipital, via the exoc- 
cipital stem to the distinct postealearine, seems to demarcate quite 
clearly the conventional lateral bounds of the occipital lobe. 
MESIAL SURFACE.—The precuneus is rather smaller than usual, and 
peculiarly fissured. The cuneus is of fair size, and well supplied with 
fissures. The callosal gyre presents nothing unusual. 
’This peculiar configuration will be described and discussed in more detailed form 
in a special contribution upon the paroccipital fissure generally. 
