Herrick, Gustatory Paths in Fishes. 433 



this way are provided extensive pathways for vagus reflexes 

 both of the gustatory and unspecialized visceral type. This 

 layer of intermediary neurones extends caudad from the vagal 

 lobes directly into the commissural nucleus and the latter is 

 probably in part a differentiation from it. The motor layer of 

 the vagal lobe of cyprinoids occupies the position correspond- 

 ing to these intermediary neurones, but the structures are not 

 exactly equivalent. These cells are probably represented in 

 the carp by intrinsic neurones which send their neurites into 

 the substantia reticularis. I have no preparations of Ameiurus 

 showing motor root fibers springing from this nucleus, such as 

 arise from the motor layer of the vagal lobe of the carp. Here, 

 as in the cyprinoids, there is no direct path between the termi- 

 ni of the primary gustatory root fibers and the motor nuclei of 

 the oblongata. The most direct return reflex path is by way 

 of the nucleus ambiguus whose neurites pass directly out to the 

 striated branchial musculature. But the dendrites of these cells 

 in no case come into relation with the termini of sensory root 

 fibers. On the other hand, they ramify in the substantia retic- 

 ularis (Fig. 30) and at least one neurone is always intercallated 

 between them and the sensory root fibers. A similar relation 

 prevails for the connections with the other motor nuclei. 



The facial lobes of Ameiurus are considerably larger than 

 the vagal lobes and each is incompletely divided into mesial 

 and lateral lobules by a shallow fissure. Both lobules receive 

 the terminals of the very large communis root of the facial 

 nerve, this root entering the lobus from in front at its ventro- 

 lateral border and spreading out in many strands which pass 

 upward through the lobe to reach its exposed surfaces. The 

 internal structure is in general similar to that of the vagal lobes. 

 There are numerous very small intrinsic neurones and larger 

 secondary neurones bordering the surface, which differ some- 

 what in form from those of the vagal lobe. 



Fig. 35 shows some of the simpler types of endings of the 

 root fibers. The interior of the lobe in occupied by intrinsic 

 neurones of type II which are similar to those of the vagal lobe: 

 (F'g- 35 ^■^^■)- The secondary connections are likewise essea- 



