344 ELIZABETH CAROLINE CROSBY 
Dorso-lateral area (figs. 7 to 10, 12, 15 to 19). This area 
forms most of the large eminence which projects from the ven- 
tro-lateral wall of the hemisphere into the lateral ventricle and 
nearly fills that cavity. Its lateral aspect is exposed in the dis- 
section illustrated in figure 2. The anterior end of the dorsal 
area is marked by the previously mentioned inward fold of the 
dorso-lateral cortex (figs. 5, 6, 7) which may be considered pri- 
mordial general pallium. In the turtle, as many writers have 
shown, there is a pallium-like infolding throughout the whole 
extent of a somewhat similar area, the dorsal ventricular ridge 
of Johnston (15). In all but its most anterior portion, the dorso- 
lateral area in the alligator is cut off from the pallial areas by 
_ the outward and downward growth of the lateral ventricle, so 
that the infolding can be plainly seen only in the anterior end 
of the hemisphere. The dorso-lateral area is bounded ven- 
trally by the intermedio-lateral area and then by the ventro- 
lateral large celled area and ventro-laterally by the anterior 
end of the nucleus of the lateral olfactory tract (figs. 7, 8). Be- 
hind the ventro-lateral areas (the lentiform and caudate nuclei 
of Johnston) it is bounded ventrally by the posterior portion of 
the nucleus of the lateral olfactory tract (fig. 12). Olfactory 
fibers from the lateral olfactory tract distribute to the dorso- 
lateral area from behind the level of the general cortex infolding 
to the posterior end of the area. Ascending somatic sensory 
fibers from the thalamus also distribute throughout practically 
all parts of this region and, in some parts of the area, these 
somatic connections alone are present without admixture with 
olfactory fibers. This purely somatic region includes practi- 
cally all the dorso-lateral area at the anterior end of the brain. 
Farther caudad an increasingly large amount of the lateral and 
dorso-lateral portions of this area receives olfactory fibers and 
only the dorso-medial portion is relatively pure somatic in type 
of correlation. The ridge of primordial general cortex implies 
a very close relation between the somatic dorso-lateral area and 
the general cortex. 
The ventro-lateral areas as they have been termed in this de- 
scription of the alligator brain are apparently directly compara- 
