139 



There is no doubt indeed that the neostriatum partly arises as such a hypopal- 

 lial ingrowth in all the higher vertebrates, though its anlage is not limited to the 

 mantle, but, also extends over the base of the bram in front of the palaeostriatum 

 (immediately behind the anterior olfactory ventricle). 



Wliilst the neo-strialuiii is separated from the archi-strialnm by 

 Hie fissiira strio-arcldstrinticd (see n\y book on the Comp. Anatomy 

 of the brain, Vol. II fig. 534), Ei.i.ioT Sjiith has riglitly pointed out 

 tiiat the boiinilary between tiie neo-sti'iatum and pahieostriatnm is 

 ciiiefly indicated by blood vessels. I may add that besides a shallow 

 groove may indicate this bonndary line (also in Reptilial, whicli 

 groove I sliall call fissura nt'o-pdltieostriaticd. 



I have now studied the ontogenetic development of the different 

 parts of (he strialnm complex in birds, mammals and man, and 

 shall give here a short review of it, leaving the archi-striatnm 

 fiirthei' ont of discussion, .since its place in brain-anatomy as the 

 homologne of the nucleus amygdalae of mammals is since long 

 established. 



Starting than with birds I may remind that practically all anato- 

 mists ha\'e accepted the division of the forebrain of these animals 

 as given by Edingkk in 1896. 



Underneath the pallium (in which the cortex is vevy primitive) 

 and continuous with it, is the hi//ierxtriatiim, forming the most dor- 

 sa,\ and most lateral part of the striate complex. This hyperstriatnm 

 is in most birds — not in all — , easily distinguished in two divisions, by 

 a thin medullary lamella : the lani'nia inednlhtris hyperstriati. These 

 divisions 1 shall call liyperstrintum superius '), and Iti/perstrintiim 

 inferiiis 'J. 



The hyperstriatnm inferius in its lateral part shows a special field 

 characterized by large cells, and richly provided with medullary 

 fibres : the ecto-striatum of authors, whicli like the rest of the 

 hyperstriatnm is separated from \\\e\inAQ\\y\\\gmeso-stri(itui)i{\)&\&eo- 

 striatnni angmentatum) by the laminn niediil/nris dorsa lis ot' nvühovs, 

 which I prefer to call /nnniui mednllnris e.cternn since it does not 

 only form the dorsal but also the lateral boundary of the meso- 

 striatum. This lamina medullaris externa is very richly provided 

 with bloodvessels as is also observed by Huntkk (Sydney) in the Kiwi. 



') This was called by Schroeder pars frontodorsalis hyperstriati. It consists of 

 tiie areae A. G. and D. of Rose's (c.f. Schroeder : Der Faserverlauf in Vorderhirn' 

 des Hühnes, Journ. of Pschych. und Neur. Bnd. IS, Erg. Heft 1912, and Rose 

 „Die zylolectonische Gliederung des Vorderbirns der Vogel". Ibidem Bnd. 21, 1914), 



') This corresponds with the areae G^, G-, G' of Rose's and with the striatum 

 parichale of Kalisher (Comp. Kalisher: Abhandl. der Akad. der Wissensch. Berlin. 

 1900, 1901. 19051. 



iO 



Proceedings Royal Acad. Amsterdam. Vol. XXVI. 



