500 Dr. F. W. Mott and Miss A. M, Kelley. [Mar. 6, 
crowded together than in the visual area. A few small pyramids are mingled 
with them. Scattered among the granules, or immediately above them, is a 
line of darkly staining stellate cells, of irregular angular shapes, giving off 
many processes. They measure on an average 25 w by 18, and are more 
conspicuous in shape and staining than in size. A line of large infra-granular 
pyramids is very characteristic of this region. These are darkly staining, 
thin, elongated pyramids, measuring from 25 w by 9 w to about 50 w by 10 uw. 
This lamination is found in its most typical form on and around the upper 
portion of the inferior wall of the Sylvian fissure, which area has, therefore, 
been termed “ Temporal A.” As it crosses the base of the fissure and ascends 
on to the gyrus above, the small crowded cells at the top of the pyramidal 
layer are less noticeable, the infra-granular pyramids become plumper, and 
more like those of the post-central area, and the stellate cells are less 
numerous. Posteriorly, the area becomes richer in cells in all layers, and the 
individual cells smaller—more nearly approaching the visual type; and here, 
again, the surface layer of crowded pyramidal cells becomes less obvious and 
finally disappears. Anteriorly the cortex, as it approaches the intermediate 
type “ R,” becomes less rich in cells, the infra-granular cells are smaller, and 
the lamination presents a less characteristic appearance. 
Visual Area. 
_? . hv VV 
Extent and Boundaries: Visual A pee 
infolded calcarine fissure, and is thus only partially visible on the surface. It 
is found on the posterior wall of the anterior limb of the calcarine fissure, on 
both walls of the posterior limb, and on the lower lip of the posterior half of 
the calcarine stem, ending within about 5 mm. of its anterior extremity. It 
sometimes only reaches to the base of the fissure, and sometimes extends on 
to the anterior wall, but it is not found on the surface on the anterior side 
of the fissure. Type “ Visual B” bounds the area posteriorly. 
Visual B.—Type “ Visual B” covers the posterior pole of the hemisphere. 
On the mesial surface its anterior boundaries are type “ Visual A,” and 
imaginary lines drawn upwards in continuation of the superior extremity of 
the anterior limb of the calcarine fissure to the dorso-mesial border ; and 
downwards from the inferior boundary of “ Visual A,” to the inferior occipital 
sulcus. It is bounded on the under surface by this sulcus, being found only 
on its superior wall; and it extends around the pole on to the dorsal surface 
for about 4 mm. Here it is bounded approximately by the rudimentary sulcus 
which is probably the homologue of the “ Affenspalte” of the apes, but it 
frequently ends within about 1 mm. of the sulcus, merging into a type inter- 
This type follows the deeply 
