400 Journal of Comparative Neurology and Psychology. 



Before proceeding with the description of the long second- 

 ary gustatory tracts from the vagal lobe we shall describe the 

 internal structures of the glossopharyngeal and facial lobes, as 

 the long tracts from all these centers can best be described to- 

 gether. 



Between the vagal and the facial lobes of cyprinoids is a 

 small tuberosity which, as pointed out by B. Haller ('96, p. 

 93 and Fig. 12), receives the glossopharyngeus nerve. It may 

 be termed the lodus glossopharyngei. It is very distinct in forms 

 like the gold-fish, Carassius, whose glossopharyngeus nerves are 

 far separated from the vagus, the sensory IX nerve entering its 

 dorsal side and the motor IX its ventral. It appears in the 

 carp at a level somewhat cephalad of that shown in Fig. 5 

 along the line of union of the vagal and facial lobes. In this 

 type it appears to receive from behind some fibers from the 

 vagus roots ; at any rate the IX and X roots are somewhat con- 

 fused in this region. In both the carp and the gold-fish it 

 receives from in front filaments of the communis root of the 

 facialis. These filaments are very clearly shown arching over 

 the dorsal side of the lobus IX in an oblique Golgi section 

 (Fig. 15, a)\ a certain part of the facial root apparently also 

 reaches the cephalic end of the lobus vagi. It would be inter- 

 esting to learn whether these facial fibers which separate from 

 the facial lobe to end in connection with gustatory fibers from 

 the mouth cavity coming in by the IX and X nerves are derived 

 from the palatine and other facial branches which also supply 

 taste buds within the mouth. 



The lobus glossopharyngei has essentially the same con- 

 nections as the lobus vagi. Fig. 16 gives an impregnation of 

 two of the intrinsic neurones of the extreme cephalic part of 

 the lobus IX in sagittal section of the brain of a young carp. 

 The sensory (gustatory) fibers of the IX nerve end among the 

 dendrites of these neurones. The neurone at the extreme left 

 does not show its neurite, but the neurite of the one marked a 

 is shown completely, arborizing in the motor IX nucleus, thus 

 completing the simplest gustatory reflex arc for the IX nerve. 



The structure oi t\\Q facial lobe (tuberculum impar, "lobus 



