Kappers, Teleostean and Selachian Brain. 43 



not all fibers of this tract end here; a larger part goes through the 

 commissura habenularis to the contralateral ganglion. 



The tractiis pallu, running at the very outside of the praethala- 

 mus and lying like a ribbon upon it, goes downward laterally of 

 the tr. olfacto-habenularis and then comes to lie ventro-laterally 

 to the nervus opticus (Fig. Ivi). It then goes more and more 

 ventrad (Figs, Ivii to Ixii) and caudad of the opticus and ends in 

 the lobi inferiores (Figs. Ixiii, Ixiv), after having wholly decus- 

 sated in the praeinfundibular thalamus region. 



Edinger, who initiated these investigations, said in his article 

 on the 'tween-brain in 1892, "Nach der Kreuzung ziehen die 

 Fasern des Mantelblindels schrag aufsteigend liber das Zwischen- 

 hirn weg und sencken sich an dessen caudalen Theilen angelangt 

 in die Tiefe des Mittelhirndaches." Haller and Catois are 

 of a contrary opinion. The latter considers the fibers of this 

 bundle to end in the lateral parts of the lobi inferiores, while 

 Haller also thinks that they end there but only partly decussated 

 and partly uncrossed. Founding his opinion on Golgi prepara- 

 tions, HousER, however, has recently confirmed Edinger's 

 original statement, though Edinger himself is no longer convinced 

 of this fact, according to his last publication op this point in his 

 "Vorlesungen," for he there says that perhaps it is a cortico- 

 mammillary tract, ending in the posterior part of the lobi inferi- 

 ores, and this I can confirm. 



The second group of fibers going from the fore-brain into the 

 'tween-brain is a combination of two tracts, the tr. strio-thalamicus 

 and a part of the tr. medianiis, forming a single whole during their 

 course in the posterior part of the fore-brain and in the praethala- 

 mus and thalamus. In the pmethalamus their fiber mass is 

 situated mesad almost in the wall of the ventriculus tertius (Fig. 

 Ivi, Plate III), and m this position it runs over the optic nerves 

 where they enter the thalamus (Fig. Iviii), after which it is crossed 

 at right angles by the com. transversa (Figs, lix, Ix). It then ends 

 in the pars posterior of the lobi inferiores, dorsally of the end of 

 the tractus pallii. 



The whole course of the tr. strio-thalamicus is easily followed, 

 so that on this bundle, which was only vaguely mentioned by 

 RoHON and Sanders, authors are pretty well agreed. In his 

 first investigations Edinger mentioned, however, that only a part 

 of the basal tract ends in the infundibular region and that another 



