149 



111 a sagittal section of the brain of a labbit of 2| cM. (fig. 14), 

 we see two proliferation centres of sti'iatiun cells. The centre 

 of proliferation marked with 1 contains archistriatic cells covering 

 the primordiuin of the palaeostr latum, the latter being its ven- 

 tral part arising from the base of the brain about the level of the 

 foramen Moin-oi, and being continnons with the wall of the preoptic 

 recess. In front of this and arising partly from the base of the 



Fig. 15. Sagittal section of the forebrain of a rabbit-embryo of 4 c.M. total length. 

 At "1 the transition of the neostriatum in the deep layer of the frontal- 

 pallium above the olfactory ventricle is seen. 



brain, partly from the mantle, we see a part of the anlage of the 

 neostriatum, marked with 2 '). 



Examining more lateral sections one sees that 2 enlarges backward 

 and unites with the anlage 1. 



I will not deal extensivel}' with the mammalian ontogeny but 

 only repi'oduce here still another section taken from a rabbit embryo 

 of 4 cM., in which the continuity of the neostriatum (2) with the 

 pallium above the olfactory ventricle is particularly evident (fig. 15). 



Also in the human embryo the two parts of the striate body 

 (I do not speak here about the amygdala) are evident,' even more 

 so than in the rabbit. 



Fig. 16 shows a frontal section through the forebrain of a human 

 embryo of 27 mM total length in front of the Foramen, Monroi. At 

 the left side of the figure the two primoidia of the striatum may 



') The cluster of cells between 2 and the base of the brain continue medially 

 into the septum. 



