502 J. n. JOHNSTON 



Fig. 19 Section 120 inicirons rostral to figure IS. In botli these sections the 

 connection of the dorsal ridge with the pallium is clear and they illustrate the 

 more embryonic conditions which prevail in the caudal pole than in the rostral 

 part of the hemisphere. 



P''ig. 20 Section at the point of connection of the hemisphere with the thala- 

 mus where the stria medullaris passes into the thalamus. In this and the next 

 two figures the lateral zona limitans appears as a diagonal light line running 

 dorsolaterally from s.v.m. to the outer surface. 



Eig. 21 Section through the foramen interventriculare. The lentiform and 

 caudate nuclei, neither of which was distinguishable in figure 20, are here quite 

 distinct. The crus in this figure separates the caudate from the nucleus of the 

 diagonal band. From this point rostrad for thirty to forty sections the crus 

 lies practically exposed on ths lateral surfac3. This condition is represented by 

 a small striatal area in the model of this brain (fig. 5). 



Fig. 22 Section through the anterior commissure. Here the general pallium 

 begins to be decidedly thickened. The motor area of the adult includes this 

 region and extends farther caudad. Forward from this level the olfactory area 

 is again continuous on the lateral, basal and medial surfaces. 



