426 'Journal of Comparative Neurology and Psychology. 



Fig. 5. A neurone of the somatic commissural nucleus of Catostomus commersoni. Golgi method. 

 X130. 



The cell body lies just to the right of the median line, in the same position as the neurone of Ameiurus 

 marked somatic commissural nucleus in Fig. 2. Several dendrites extending across the meson soon pass 

 out of the plane of the section. One large dendrite spreads throughout the whole ventral part of the 

 combined funicular nucleus and spinal V nucleus; another spreads throughout the whole of the dorsal 

 part of the formatio reticularis. 



Figs. 6 to 10. A series of transections through the region of the commissura infima in the adult 

 conger eel (Conger conger), all drawn to the same scale. Wiegert method. X 26. 



Fig. 6. Section through the brain of Conger just caudad of the vagal lobes, passing through the 

 visceral commissural nucleus which is composed of a dense mass of neuropil and a cluster of small cells in 

 the middle. Unmedullated fibers cross the meson, constituting the visceral commissura infima; others 

 pass as uncrossed secondary visceral tracts to the formatio reticularis. Dorsally of this nucleus is the 

 most cephalic part of the somatic commissura infima, consisting of medullated fibers from the caudal 

 ends of the tubercula acustica. The somatic sensory field laterally of the nucleus extends caudad from 

 the tuberculum acusticum to the funicular nuclei. It contains both neuropil and fine medullated fibers 

 diffusely distributed. Internal arcuate tracts pass from this field into the ventral commissure. 



