581 
of Edinhimfli, Session 1865 - 66 . 
and in all the specimens the fissure of Rolando {R) extended up- 
wards as far as the great longitudinal fissure, and formed with its 
fellow the sides and apex of a V-shaped figure. The lobule of 
the second ascending parietal convolution of G-ratiolet (posterc- 
parietal lobule — Huxley) reached as far back as the external per- 
pendicular fissure (parieto- occipital fissure), and presented a sub- 
division into an internal (5") and external (5') portion ; each of 
which again, though somewhat more strongly marked in B than in 
A and (7, exhibited signs of sub-division into secondary lobules. 
The bent or angular convolution (pli courbe) (6 6) varied some- 
what in its arrangement in the three specimens. In A it commenced 
much lower down in front of the Sylvian fissure than in B and C. 
The length of its ascending part, from its commencement to the 
apex of the fissure, was in the first named Ij^tb inch, whilst in the 
others it was considerably less. In all three brains it was partially 
broken up into smaller convolutions by secondary fissures. In A 
its descending part was directly prolonged into the middle temporo- 
sphenoidal convolution, as in the brains figured by G-ratiolet and 
Marshall. In B and G its continuity superficially with this con- 
volution was broken by a cross intersecting fissure. Not only in 
the brain of the Chimpanzee, but in those of all the apes in which 
the various parietal convolutions are differentiated, the fissure which 
separates the angular convolution from the second ascending parietal 
and its posterior lobule is so clearly marked that it deserves to be re- 
cognised by a distinctive term ; but as none has as yet been applied 
to it, I would suggest that it should be called the intra-parietal 
fissure {I P). This fissure commences anteriorly behind the fissure 
of Eolando, at first ascends almost parallel to it, and then runs 
backwards and joins posteriorly the parieto-occipital fissure. 
In the brain (G) the external perpendicular (parieto-occipital) 
fissure (E P) on each side was unbroken by the passage across of 
either the first or second bridging convolutions, and the opercular 
edge was as sharp and well-defined as in the brains figured by G-ra- 
tiolet and Van der Kolk and Vrolik. But in B, whilst this arrange- 
ment existed in the right hemisphere, the left exhibited an im- 
portant variation. From the posterior and outer angle of the left 
postero-parietal lobule a narrow, but clearly- marked convolution 
(a, fig. 2), half an inch long and ^th of an inch wide, arose. It 
