155 



Schroeder) and those of the mammalian striatum (which are known by the worlis 

 of MoNAKow, Dejerine, Wilson, the Vogts, Ramsay Hdnt, Lewy), shows in many 

 respects a great resemblance. 



In both classes it is chiefly the internal segment of the dorsal thalamus (nucl. 

 anterior and nucl. medialis) together with the ventral thalamus and subthalamic 

 and peduncular region, which are connected with the striate body (as is already 

 the case in Reptiles). 



So in mammalia a connection is known to exist between the nucleus anterior 

 thalami and the caudate nucleus (a connection which 1 can confirm for the mar- 

 supials). It seems possible that this connection is homologous or at least analogous 

 to the fibre tract which Wallenberg showed to exist between the medio-dorsal 

 part of the ueo-striatum in birds and the nucl. anterior dorsalis in these animals. 



The antero-lateral part of the striatum of birds, which may be homologous to 

 the anterior part of the putamen of mammals has connections which are homo- 

 logous to the mammalian, if at least the ventral peduncular nuclei of birds are 

 homologous to the corpus subthalamicura and substantia nigra of mammals which 

 is very likely so. 



Moreover in both classes this striatal region seems to give fibres to the com- 

 missura supraoptica dorsalis of Meynert (which also contains fibres from the 

 palaeo-striatum augmentatum). Concerning the paleostriatum augmentatum (meso- 

 striatum in birds), it may be that this, partly at least, has to do with trigeminal 

 functions. The considerable enlargement which the original palaeostriatum (small 

 as it is in Amphibia) acquires in Reptilia (chiefly in the Crocodile) and in 

 birds, may be due to projections of the trigeminus, which acquires a very important 

 size and function in the crocodile and is of prepondering importance in birds, the 

 more so since smell and taste are of so little importance here, and the oral sense 

 is so important for life, as 1 pointed out in 1908. (Folia Neur.). 



Also the fact that in Ornilhorrhynchus and in Elephas (E. de VriesI, the 

 palaeostriatum is so well developed may support this point of view, since the 

 trigeminus is of prevailing importance here, (the Vth nerve is at least three times 

 larger in Monotremes than in other animals and in the Elephant it provides the 

 trumpets sensibility of muscles and skin). The sensibility provided by the trige- 

 minus to facial muscles is generally of great importance as is proved by the 

 disturbances of tonic innervation of the face, so often seen in man as a conse- 

 quence of striatial lesions. 



As far as concerns birds also Roger's ^} experiments seem to prove this conception. 



Of course the connections of the striate body are not exhausted with this 

 enumeration, so f. i. there remains to be mentioned the fibre system proceeding 

 from the nucleus ruber to this body as demonstrated by v. Monakow and others. 

 It is interesting in this respect that Schroeder (I.e.) even mentions — for birds — 

 a direct continuation of the brachium anterius cerebelli, to the palaeostriatum 

 augmentatum of birds. This sort of connections on account of their cerebellar 

 component fall also in the range of motor coordinations. (G.f. also Lewy')). 



The exact character of all these systems has not yet been sufficiently scrutinized, 



M An experimental study on the corpus striatum in the pigeon. Journ. of comp. 

 Neur. Vol. 35., 1922. 



') Lewy, Die Lehre voni Tonus und der Bewegung. Jul. Springer, Berlin, 1923. 



11 

 Proceedings Royal Acad. Amsterdam. Vol. XXVI. 



