424 J. B. JOHNSTON 
ventricle is reached (figs. 45, 44). At the same time the tail of 
the caudate nucleus appears between the dorsal and basal lobes 
of the ventricular ridge. The large-celled nucleus now surrounds 
the temporal horn of the ventricle and occupies the pallial sur- 
face medial to the nucleus of the lateral olfactory tract. Now 
the large bundle of the stria terminalis goes upward and forward 
from the large-celled nucleus, as above described. Finally the 
large-celled nucleus disappears from the sections at the level of 
the stria medullaris. 
Thus the general pallium extends forward in the basal wall to 
the tip of the temporal pole. Its cells in this region are of vari- 
oys forms and are irregularly scattered and there is an intimate 
merging of the pallium with the large-celled nucleus of the amyg- 
daloid complex. There is no area or avenue of continuity of 
the cell masses of the pallium with those of the brain stem. There 
is, however, continuity of the pallium, the large-celled amygda- 
loid nucleus and the lentiform nucleus of the corpus striatum. 
The lentiform nucleus imbeds the lateral forebrain bundle and is 
therefore comparable with the somatic area in the lateral wall of 
the selachian forebrain. In the turtle there is continuity through- 
out the cell masses related to the afferent and efferent fibers 
primarily somatic in function in the lateral bundle, or crus. 
In the fishes the somatic area is continuous with the sensory 
centers of the thalamus. That this connection has been lost in 
the turtle may be attributed to the greater development of the 
hemisphere which has elongated the crus and drawn the lenti- 
form nucleus away from the thalamus. 
The general ‘pallial portion of the hemisphere consists there- 
fore of (1) a broad, rather thin wall forming the roof and caudal, 
pole of the hemisphere; (2) bounding this laterally and ante- 
riorly, a pallial thickening which has a peculiar structure; and 
(3) a temporal area of simpler structure which is intimately con- 
nected with the dorsal ventricular ridge. This ventricular ridge 
might, indeed, logically be listed as a fourth part of the general 
pallium. 
That these four regions are intimately related and constitute 
one complex area in the forebrain, comparable to the olfactory 
