METATHALAMUS AND HYPOTHALAMUS. 



277 



mamillare. The latter is surrounded by its medullary capsule, in which the fornix 

 has now disappeared, and it sends away above the tegmental bundle (the tractus 

 mamillo-tegmentalis), and the tractus thalamo-mamillaris (the bundle of Vicq 

 d'Azyr), which at first pass along united. 



The nucleus lateralis and medialis thalami allow the posterior end of the nucleus 

 anterior to extend between them dorsally; ventrally they flow together. Here 

 begins the region of the nucleus ventralis. The more posterior portion of the ansa 

 lentiformis streams in here, and other fibers from the corpus striatum go to the gray 



Nucl caud. 



Niicl. ant thai' -, 

 Lain. Hied int 1 

 Tr. thai, rnam j 

 Corp callos 

 Nucl lat 

 Tsenia 

 Nuel vent *" 

 Nucl med "^ 

 Lam. med ext - 

 Ansa lentif 

 Zona incditOK 



Corpus subthal 

 Fes peduncuh 



Col. fornicis vv^, 

 Corpus main i x 

 Med. capsule of ^ ,3 ^ 

 corpus mam 



Tuber cinereum 



fNucl. amyg. 



Lob. temper. 



Fig. 178. 



nuclei of the regio subthalamica. The lamina medullaris interna thalami has become 

 much richer in fibers, and between the latticed layer and the lateral nucleus there 

 develop the tracts of the lamina medullaris externa thalami. The stratum zonale 

 is very perceptibly diminished, and the taenia is to be seen more clearly. The 

 lenticular nucleus, the elaustrum, the capsulee, and the cortex of the insula, with the 

 exception of somewhat alter.ed forms, present nothing that differs essentially from 

 the sections previously shown. In the white medullary substance the long asso- 

 ciation-tracts may still be sought for in the same situations where they lay in the 

 section shown in Fig. 174. 



