4o6 "Journal of Comparative Neurology and Psychology. 



cephalic root of this nerve. The spinal V tract just before reach- 

 ing the region of the funicular nuclei receives the vagal general 

 cutaneous root (Fig. 6). The tract is accompanied by a variable 

 amount of substantia gelatinosa Rolandi within w^hich some of its 

 fibers end. In most teleosts this structure seems to be reduced, 

 possibly by the crowding due to the great development of the tuber- 

 culum acusticum and vagal lobes, save in the lower part of the 

 oblongata, so that by far the greater part of the spinal V tract ends 

 in the region of the funicular nuclei or further caudad in the spinal 

 cord. In some teleosts there is a well differentiated nucleus of the 

 spinal V tract in the funicular nucleus region; in others this 

 nucleus and the nucleus funiculi are confused. In all cases a con- 

 siderable proportion of the trigeminal root fibers pass caudad 

 beyond the nucleus funiculi into the dorso-lateral funiculus of the 

 spinal cord, where they can be separately followed for several seg- 

 ments before being lost among the other fibers of this funiculus. 



In fishes where the taste buds are very numerous in the outer 

 skin (cyprinoids and siluroids) the nerves of these cutaneous 

 organs all enter the brain by the communis root of the facialis nerve 

 and terminate in a specially differentiated center, the lobus facialis. 

 In other fishes where they occur these fibers enter the brain by the 

 same nerve root, but end in the vagal lobe along with other gusta- 

 tory fibers from the inside of the mouth which enter by the VII, 

 IX and X nerves. The vagal lobe in all cases also receives from 

 the IX and X nerves a large number of general or unspecialized 

 visceral fibers which have no peripheral connection with taste 

 buds. These visceral fibers are more numerous in the more cau- 

 dal rootlets of these nerves, coming from the cesophagus and 

 abdominal viscera, than in the more cephalic rootlets, coming from 

 the gills and palate where taste buds are abundant (Herrick, '99, 

 p. 246). 



The most caudal sensory root of the vagus nerve, immediately 

 after entering the oblongata, turns caudad to end in the commis- 

 sural nucleus of Cajal near the median line caudad of the vagal 

 lobes, some of the terminal fibers crossing in the commissura infirna 

 to end in the nucleus of the opposite side (Figs. 5, 7, 13, 14, 15). 

 This root is probably chiefly of general visceral function, not gusta- 

 tory, and in the figures is termed the descending sensory root of 

 the vagus. 



In the highly developed teleostean brains which we are here con- 



