148 



tlie groove between hyperstrial imi c and archistriatum E (the fissura 

 strio-arohistriatica) is visible (but not indicated). 



Resuming 1113' resnils concerning birds, 1 may conclude that here 

 (apart from the arcliislriatum or amygdala) at least two chief divi- 

 sions of the striatum may be distinguished : liie palaeostriaium, 

 which is enlarged to a palaeosfridhim (tugmentdtum {ov meso-sh-mlum) 

 and which arises enlirely froin the base of the brain in front of 

 the recessus praeopticus, and the Jiij [)ersh latum of which Ihe upper 

 part arises entirely from the mantle (hyperstriatum superius), while 

 Ihe ujulerpart (hyperstriatum hifnius), arises from the mantle 

 (laterally) as well as from Ihe l)ase of the brain in front of the 

 lialaeostrialuui. Bolh parts of llie hypeistrialum thus show the fact, 

 that intraventricular protrusions of striatal type may originate from 

 Ihe pallium as well as from Ihe base of the brain, as I already 

 pointed out for Ihe primary cpisli'iafum in bony fish(>s, and as 

 was pointed out by Ei.i.. Smith for the neostriatum of Reptiles. 



Before dealing with the question whether Ihe hyperstriatum superius 

 of birds is included in the neostriatum of mammals (as the hyper- 

 striatum iiiferius is), or if it is homologous to the claustrum, I shall 

 shortly describe the embryonic development of the striate body in 

 the rabbit and in man, about which already His '), Hochstkttek ') 

 and Miss Hines ') have given us such valuable informations. 



Fig. 14. Sagittal section of the forebrain of a rabbit-embryo of 

 21/2 cM. total length. 



1 = contains ventrally the palaeostriatum, arising on the 



level of tlie foramen Monroi. 



2 = the neo-striatum arising partially from the mantle 



1) His, Die Enlwicklung des menschlichen Gehirns, Leipzig 1904. 



') HocHSTETTER. BeitrSge zur Entwicklung des menschlichen Gehirns. Deuticke, 

 Wien i;»20. 



3) HiNEs. Studies in growth and differentiation of the telencephalon in man. 

 Journ. of comp. Naur. Vol. 34, 1922. 



