1908.] Cell Lamination of Cerebral Cortex of the Lemur. 495 
neopallium and the archipallium. In making the diagrams we have, therefore, 
not attempted to map out the whole cortex into arbitrary divisions. We 
have marked the “focal” areas in each case with larger figures, and the 
“peri-focal ” areas with figures of the same type but smaller. Blank spaces 
have been left on the diagrams to indicate the intermediate indefinite areas 
which show mixed characteristics, as it cannot be definitely stated that they 
belong to the one type or to the other. , 
Special mention may be made of the intermediate areas which lie anteriorly 
to the visual area, both on the mesial and lateral surfaces. The cortex in 
this region of the brain is particularly rich in cells. The pyramidal layer is 
well developed, the individual cells being rather smaller and more numerous 
than the pyramids of the post-central and temporal types, but not so small 
and less closely packed than those of the visual area. The granule layer 
forms a conspicuous band, rather deeper though again less closely packed 
than in the visual area, and the individual cells here also are rather larger. 
A line of darkly staining stellate cells is seen above the granule layer, 
and a line of large pyramids is found which resemble those seen in the 
temporal area but which are not so large as those found in its most typical, 
or “focal” region.* We have not mapped out this cortex as a definite type 
covering a (lefinite area. Though at its posterior border the point at which 
it ends and the visual type begins can be observed in longitudinal sections 
of this part of the brain, its anterior border is very indefinite. It merges 
into the temporal and post-central types so gradually that unless sections from 
the focal regions of these areas are compared with a section from its posterior 
Margin, no very appreciable differences in:structure can be seen. The cortex 
of this region thus seems to be intermediate in structure—as it is in position 
—to the post-central, temporal, and visual types. It is probable that in this 
area lie the homologues of the “parietal” and “ visuo-psychic” types 
‘described by Campbell in the higher apes. These types would tend to become 
more definite in character and extent as the parietal lobe becomes more 
highly developed. 
Motor Area.t 
Pw @ 6 oa 
eseee|—This type covers that part of 
Katent and Boundaries: Motor A 
the dorsal and mesial surfaces which lizs between the posterior end of the 
* It is regretted that, owing to the number of illustrations being necessarily limited, a 
reproduction of the drawing of this type cannot be given. 
t This area was mapped out by the experimental method by Professor Halliburton and 
Dr. F. W. Mott, and has been described in a paper now in press for the ‘ Proceedings of 
the Royal Society.’ 
VOb. Xk.x.-—B. BB 
