151 



aniage continuing still sonoe distance in front, being continuous not 

 onlv with tiie base of tlie brain, but also with the mantle of the 

 frontal pole, immediately above the olfactory ventricle (this is why 

 His has called it cj'us epirkuiicum). 



The fissure between the neo- and palaeostriatum becomes less and 

 less deep during further development. In an embryo of 27 centimeters, 

 it has become very shallow, by the |)repondering development of 

 the neostriatum, which more and more overlaps the palaeostriatum, 

 as we found it also to be the case in birds with the hyperstriatum 

 inferius. 



The tissura neo-palaeostriatica may however still be seen in the 

 full-grown human cerebrum (f. i. about the level of the conim. 

 anterior, fig. 17: F.N.P.S.) forming the ventro-mesial ijorder of the 

 caudate nucleus. 



Fig. 17. Transverse section through the 

 corpus striatum of an adult man on 

 the level of the comm. anterior (c. a ). 

 N.S. = Part of the Neostriatum (nu. 

 caud.). 



F.N.P.S. = Fiss. neo-palaeostriatica. 

 P.S. = Palaeostriatum icovered by 

 the taenia semicircul.i 



Underneath this fissure runs the .•itria-semicirculans, which covers 

 here some small vestiges of grey substaiice lying on the ventricular 

 side of the capsuhi interna and still belonging to the palaeostriatum, 



priory to the resorptive function of botli choroid plexusses and Virchow-Robin 

 spaces (Compare also my book on Gomp. Anatomy of the N. S. p. 820 and Weed 

 Contributions to Embryolog. publ. by the Carnegie instil. Vol V. 1917). 



