J 44 



being entirely derived from the mantle '), not from the basal part 

 of the brain. 



Olf. b. 



Fig. 8. Sagittal section of the forebrain of a chickembryo of 6 days 

 (lateral to fig. 7) d = palaeoslriatum augmentatum (= meso- 

 striatum) c = hyperstriatum inferius, d = hyperstrialum superius. 



In fig. 9 only a small part of the palaeostriatnm (b.) is seen, viz 

 that part which is conlinnons with the recessus praeopticus. 



Fig. 10 is interesting to us because it shows that the hindpole of 

 the striatum nearly only consists of hyperstriatum inferius (c), the 

 lamina medullaris hyperstriati (in this stage of development) ending 

 only little beyond the contact of hyperstriatum superius and pal- 

 lium. In the same figure (but better in 11 and 12) is seen thai the 

 hyperstriatum. inferius is continuous with the base of the brain 

 (whilst more laterally it is continuous in the pallium). 



Of the palaeostriatnm besides the part that is continuous with 

 the recessus opticus a frontal part is seen in fig. 10, seemingly 

 separated from the hindpart by a recess of the ventricle. This is 

 however only seemingly so, this aspect being caused by the fact 



') One might ask if the part called hyperstriatum superius here is not partly 

 the "mediale Sagittal-VVulst" of the cortex with which the hyperstriatum superius 

 in many birds (f. i. the Gacatua) coalesces. This however is not so here, though 

 later the hyperstriatum superius continues in the medio-dorsal mantle, without 

 showing any medullary limitation. 



