330 



THE BRAIN OF THE TIGER SALAMANDER 



Figure 16. — Diagram of the chief afferent tracts to the ventral thalamus (p. 239). 



Figure 17.- — Diagram of the chief efferent tracts from the ventral thalamus (p. 240). 



Figure 18. — Diagram of the chief connections of the "peduncle" (nucleus of the tuberculum 

 posterius, pp. 50, 217). Many shorter connections are omitted. For the connections of the 

 ventrolateral neuropil see chapter iii and figure 23. 



Figure 19. — Diagram of the diencephalic connections of the amygdala (pp. 52, 248) and of 

 some of the connections of the interpeduncular nucleus (chap. xiv). 



Figiire 20. — Diagram of the connections of the habcnula. In the stria medullaris thalami the 

 components are arranged in the fore-and-aft order in which they ascend, as also are the 



decussations in the habenular commissure (compare the horizontal sections, figs. 25-36). 

 Efferent fibers from the habenida enter three tracts (fr./iab.t.,f.refr., and tr.hab.th.). The afferent 

 fibers are numbered as in the analysis of the stria medullaris in chapter xviii: 



1. Tr. olfacto-habenularis medialis 



2. Tr. olfacto-habenularis lateralis 



3. Tr. olfacto-habenularis anterior, ventral division 



4. Tr. olfacto-habenularis anterior, dorsal division 



5. Tr. cortico-habenularis lateralis 



6. Tr. amygdalo-habenularis 



7. Tr. septo-habenularis 



8. Tr. cortico-habenularis medialis 



9. Tr. cortico-thalamicus medialis 



10. Tr. olfacto-thalamicus 



11. Tr. thalamo-habenularis 



12. Tr. tecto-habenularis 



Not shown in this figure is the tr. pretecto-habenularis and a probable tr. strio-habenularis. 



Figure 21. — Diagram of the chief afferent connections of the tegmentum isthmi (p. 179). 

 Most of the tracts here indicated end in both the isthniic and the trigeminal tegmentum. 

 For the connections of the interpeduncular nucleus and its neuropil see chapter xiv. 



Figure 22. — Diagram of the most direct connections between the retina and the peduncle. 

 Optic tracts and efferent paths from the peduncle are drawn in full lines, internuncial connec- 

 tions in broken lines, and thick myelinated fibers in heavier lines (chap. xvi). 



