1908.] Cell Lamination of Cerebral Cortex of the Lemur. 501 
mediate to the visual and temporal types ; which is also its boundary between 
this sulcus and the inferior occipital. 
Characteristics: Visual A (fig. 10)—The depth of the cortex is about 
1 mm., the molecular layer measuring about 0°15 mm., the pyramidal layer 
about 0-4 mm., the granule layer 0°15 mm., the pallid zone about 0°15 mm., 
and the polymorph layer only about 0°1 mm. in depth. The pyramidal cells 
are small and closely packed together, giving a crowded appearance to this 
area. Stellate cells are present above the granules. The granule layer is a 
prominent feature. The cells are smaller than those forming the granule 
layer in the post-central and temporal types, and are closely packed 
together ; thus presenting under a low power a very characteristic appear- 
ance. Above this layer a pallid zone may be observed, which is not, how- 
ever, very pronounced, and is not so deep as the one described below. Large 
solitary cells are sometimes found in this position. Above this ill-defined 
pallid zone there is a suggestion of a duplicated line of granules in some 
scattered cells which lie at the bottom of the pyramidal layer. Below the 
granule layer there is a pallid zone about 0°15 mm. in depth, in which are 
scattered a few granules, pyramids, and polymorph cells. Both in this zone 
and above the granules are found the large solitary cells of Meynert—cells 
having a blunt triangular or roundish shape, and large nuclei, and measuring 
on an average 25 by low. The polymorph layer is shallow and crowded 
with cells. e 
Visual B.* —This cortex is a little deeper in the pyramidal and 
polymorph layers than “ Visual A,’ becoming gradually deeper as it 
approaches the intermediate areas between it and the temporal and parietal 
types. The cells of the pyramidal layer are still small, but are not so crowded 
as in “ Visual A.” There are large pyramids to be seen both above and below 
the granules, measuring about 20 to 304 by 5m. Scattered among the supra- 
granular pyramids are a number of stellate cells, resembling those described 
in the temporal area. The granule layer is also less crowded, and the indi- 
vidual cells rather larger than in “ Visual A.” The pallid zone below the 
granules is not so conspicuous ; and the zone above them, with the suggestion 
of duplication of the granule layer, has disappeared. The solitary cells of 
Meynert are not present, their place being taken by the infra-granular 
pyramids mentioned above. 
Archipallium [a-="4. (Olfactory Area.) 
Extent and Boundaries—The olfactory area covers the under surface of the 
temporal lobe. It is bounded superiorly by the rhinal fissure, inferiorly 
* See footnote * on p. 495. 
