■ JO journal of Comparative Neurology and Psychology. 



of the gadoids and on the barblets of Ameiurus function similarly 

 as organs of taste, that the fishes can localize pure gustatory 

 stimuli applied to these organs and that ordinarily both taste and 

 touch cooperate in finding food by means of them, though the two 

 sensation factors may be experimentally isolated by training. 



Accordingly, I have reexamined the vagal lobes and their con- 

 nections in the cod and find that the gustatory nerves of the somatic 

 type, those from the outer skin, and the gustatory nerves of the 

 visceral type, from the mucous membranes, do have distinct cen- 

 tral connections, though in quite a different way from that found 

 in the catfish. The facts are these [cf. Fig. 2). 



The vagal lobe of the cod is internally divided by a longitudinal 

 septum into median and lateral lobules of about equal extent 

 (Figs. 3 and 4). The median lobule is primarily visceral and 

 receives the gustatory roots of the IX and X nerves, as in other 

 fishes. The gustatory root of the facial nerve, which carries prac- 

 tically all of the fibers from taste buds in the outer skin and a 

 smaller number of fibers from the mucous membrane of the ante- 

 rior part of the mouth (ramus palatinus VII, etc.), terminates in 

 both lobules, but chiefly in the lateral one. While I have not been 

 able to demonstrate that the facial fibers which reach the median 

 lobule are from visceral buds within the mouth, yet this is very 

 probable. In any case, it is clear that the lateral lobule is prima- 

 rily, if not exclusively, the terminal nucleus for the gustatory fibers 

 of the somatic type; that is, it is the physiological, if not the mor- 

 phological, equivalent of the facial lobe of siluroids and cyprinoids. 



The two important papers on the brains of teleosts published in the Gegenbaur Festschrift 

 (GoRONowiTSCH '96, and Haller '96) give figures of the medulla oblongata of Lota vulgaris, a form 

 closely allied to Gadus. Both of these authors were so dominated by the endeavor to reduce all cranial 

 nerves to segmental units of the spinal type as to vitiate to some degree their obserpation. Their two 

 figures of the brain of Lota bear very little resemblance to one another, or to the brain of Gadus, whic h 

 is somewhat remarkable in view of the fact that both authors were studying the internal courses of the 

 nerve roots microscopically. Haller shows (Plate I, Fig. 6) a series of four pairs of enlargements in 

 the vagal region, the first belonging to the IX nerve, the others to the vagus. The figure of Gorono- 

 wiTSCH (Plate I, Fig. 3) is evidently much more accurate as to externals, but is in part incorrectly inter- 

 preted. He figures a lobus facialis (my lobus vagi lateralis), to which he correctly traces the communis 

 VII root; a lobus glossopharyngei (my lobus vagi medialis), to which he correctly traces the IX and X 

 nerves; a lobus vagi impar (my visceral commissural nucleus), to which he traces vagus fibers; and a 

 lobus vagi which corresponds to my somatic commissural nucleus. The error in the latter point is 

 due to his failure to recognize the distinction between the somatic and visceral regions of the oblon- 

 gata. With this point in mind it is impossible to confuse the vagal lobes with the somatic com- 

 missural nucleus. 



