153 



the inesostriatiim (palaeostriatiim angmentatiim) to do tlie same '). 

 Whereas however the daik blue ooluiir in the striatum of mammals 

 is confined to the part of the palaeostriatiim lying laterally to the 

 internal capsiila (the globus pallidus) in birds the deep slain reaches 

 the ventricular side of the palaeostriatiim. This ditfereuce is appar- 

 ently due to the accumulation of myelinated fibres in the capsula 

 interna in mammals, myelinated fibres being insensitive to this 

 reaction. Only in such mammals where the capsula is less dense 

 may the blue colour penetrate in it, as Spatz found to be the case 

 in Ungulates '). 



It may be mentioned here, that as in birds (fig. 11 and 12) also 

 in mammals the mesial part of the palaeostrialum may continue some 

 distance caudad underneath the neostriatum, viz. under the caudate 

 nucleus. This substantia palaeostriatica caudata accompanies the 

 stria semicircularis on its lateral side, and in some mammals 

 (Elephas) is separated from the unci, caudalus (neostriatum) by a 

 fissure (the continuation of the fissura neo-palaeostriatica), or a 

 medullary lamella with bloodvessels. This may be also observed 

 sometimes in man. 



I still will call attention to the fact that the neo-palaei»strialic 

 fissure, generally best indicated on the level of the commissura 

 anterior, may acquire a much more pronounced character in patho- 

 logy. An example of this is given by the case Longery described 

 by Dkjkrine in his text book'). 



In this case the hypertrophied ependyma (Ep. fig. 18), is especially 

 thick at the limit between neostriatum and palaeostrialum (at X in 

 fig. 18), filling up the neo-palaeostriatic groove. 



The striatum in this case is further interesting to us, because it 

 shows such a marked similarity with the striatum in birds, which 

 is due to Ihe reduction of the pallium in this case (a hydro- 

 cephalic). As a consequence of this reduction the capsular fibres 

 are much less developed than in normal condition, which attributes 

 to the avian aspect of this corpus striatum. 



It needs not be repeated here that the division made in the mammalian 

 neostriatum in a pulamen and caudate nucleus is not an intrinsic one. The putamen 



M [n birds the deepest blue is shown by the "Sagittalwulst", specially its frontal 

 part, tben comes the meso-striatum, then the caudal part of the hyperstrialuni 

 inferius. fn the thalamus the nucl. rotundus chiefly acquires this colour. 



-) That the palaeostrialum is not confined to the globus pallidus alone is also 

 proved by the figures of Hochstetter's embryologie collection, where the early 

 differentiating region is seen to penetrate into the capsula. 



') Dejerine. Anatomie des centres nerveux, Tome II, fig. 202. 



