THE INTEBBRAIN OR THALAMENCEPHALON. 



131 



cortex: Tractus cortico-hahenularis. Both together form the Tcenia 

 thalami (see Fig. 100). Several smaller afEerent bundles need not be men- 

 tioned. Eemember simply, that in the Ggl. habenulse an important con- 

 necting bundle ends, which is composed of fibers from the posterior olfactory 

 lobe and fibers to the olfactory cortex. 



A large part of the fibers of the Tasnia thalami end, not direct in 

 ganglia of the same side, but cross to the one on the opposite side through 

 the Commissura habenularis. The tsenia consists of a medullated and a 



Opticus med. fas. »- 



Tr. haben.-pedunc. 



Nucl. rotundus. 



Corp. genie. lat. 



Tr. strio-thalamicus ■ 



Fornix 



Pig. 81. — Frontal section through the dorsal portion of the thalamus opticus 

 of the "blind snake" •- Anguis fragilis. Golgi method. 



non-medullated portion; the same is triie of the commissure. Figs. 99 and 

 100 show the plan of the connection of the olfactory apparatus and the 

 Ggl. habenulse. 



The more median of the two ganglia sends out a bundle ventrally: 

 Tractus habenulo-peduncularis, or Fasciculus retroflexus (see Figs. 64 and 

 80). Its fibers traverse the whole base of interbrain and midbrain and end 

 not far posterior to the Oculomotorius in a small ganglion lying quite ven- 

 tral in the base of the medulla, in the Corpus interpedunculare (Fig. 65). 

 Here they break up, and their terminal fibers decussate with those of the 



