238 



nucleus praeopticus as well. Elsewhere I shall show reason for dist- 

 inguishing two functionally separate tracts, one properly called olfacto- 

 habenularis and one arising from a somatic area in the forebrain, 

 which may retain the name tractus taeniae. 



Fig. 11. 



Fig. 13. 



Fig. 12. 



Fig. 14. 



To find an interpretation of the "tractus taeniae" of Kappers in 

 Chimaera it must be stated that in selachians the tractus pallii does 

 not decussate completely behind the chiasma. Part of the fibers as- 

 cending from the hypothalamus pass up on the same side, forming a 

 direct tractus pallii. In ganoids and teleosts most of the fibers of 



