Herrick, Gustatory Paths in Fishes. 409 



ing from the chief secondary gustatory neurones of both the 

 vagal and facial lobes, is one of the most distinctive features of 

 the teleostean brain. In the two groups here treated, particu- 

 larly, it attains enormous dimensions, constituting the "Sekun- 

 dare Vagus-Trigeminusbahn" of Maysek. whose excellent de- 

 scription ('82, p. 318) is fully confirmed. It is included in the 

 "system y" of the descriptions of Goronowitsch ('88, and 

 'q6). The curious notion of B. Haller ('96, p. 92) that this 

 is a descending tract from the cerebellum and other higher cer- 

 ebral regions to the sensory centers in the vagal lobe need not 

 detain us, for he gives no evidence for such a view. The com- 

 mon designation of this tract as "secondary vagus bundle" is 

 inadmissible, since in all fishes it contains secondary glosso- 

 pharyngeus and facialis fibers also, the secondary facialis fibers 

 preponderating in siluroids. Moreover, there are other second- 

 ary vagus tracts for general cutaneous and other types of fibers, 

 besides the descending and short gustatory paths described in 

 the preceding section. 



The ascending or central gustatory tract takes its position 

 ventrally and mesially of the spinal V and descending secondary 

 facialis tracts and partly enclosing them (Fig. 5, a.s.X.). It 

 ascends to the level of the superficial origin of the sensory tri- 

 geminus root from the oblongata, where it turns mesially and 

 dorsally to enter its own terminal nucleus (superior secondary 

 gustatory nucleus. Fig. 20). The axial portion of this nucleus 

 was termed by Mays er "Rindenknoten" and by Johnston ('01) 

 secondary vagus nucleus. It is included in the "Uebergangs- 

 ganglion" of Mayser's descriptions, this latter group of cells 

 being very complex and not as yet fully understood. Its hom- 

 ologies are considered in the final section of this paper. 



It lies in the dorsal part of the isthmus ventrally of the 

 line of fusion of the valvula cerebelli with the body of the cere- 

 bellum. Typically it lies near the median line and projects into 

 the aquaeductus, but in some cyprinoids it is so greatly enlarg- 

 ed as to reach also to the lateral surface of the brain at the isth- 

 mus and there project as a distinct tuberosity between the cau- 

 dal end of the tectum opticum and the tuberculum acusticum 



