147 



In fig. 13 we see the division of the palaeostriatiim by the lamina 

 raedullaris interna, the inner segment of the palaeostriatnni being 

 the basal nucleus or palaeostriatuni prin)itivuni. In this tigiire also 



Fig. 12. Sagittal section lateral to fig. 11. Note the dorso-caudal 

 tail of the mesostriatum [bi the substantia palaeosti'iatica 

 caudata, underneath the caudal pole (o of the neostriatum. 



Fig. 13. Sagittal section of the forebrain of an 11 days chickembryo lateral to 

 fig. 12. The hyperstrialum superius (rf) is smaller, the hyperstriatum 

 inferius (c) larger here than in fig. 12 The latter shows its transition 

 in the pallium. £ 5 = ectostrialum, E'^secund. epistnatum or archi- 

 striatum; between the latter and b the basal nucleus. 



