No. I.] THE CRANIAL NERVES OF AMPHIBIA. 187 



however, arises from von Lenhossek's discovery (39), that the 

 fibres of the superficialis major are not connected with the 

 geniculate ganglion. As we shall see later, the innervation of 

 the mouth (in the broader sense) is a complicated problem. 



The homology of the R. mandibularis internus with the 

 chorda tympani was first briefly discussed by me in the articles 

 in the Zoologischer and Anatomischer Anzeigers. Since then 

 Gaupp (25), reasoning from topographical relations, has come 

 to a similar conclusion. 



In Urodela the R. mandibularis internus, or chorda tympani, 

 is represented by the R. alveolaris VII, which usually, for part 

 of its course, proceeds in a canal in the lower jaw. Fischer 

 was not able, apparently, to determine its distribution clearly. 

 He mentions, however, twigs to the skin. This is probably 

 either incorrect, or such twigs leave the proximal part of this 

 branch and are composed of cutaneous fibres not properly 

 belonging to the R, alveolaris. Von Plessen and Rabinovicz 

 do not mention its final distribution. 



Although anticipating somewhat, it may be here noted that 

 Ewart describes a bundle of fibres continuous with the root of 

 the R. palatinus and running forwards to end in the "fold of 

 mucous membrane lying between the hyoidean and mandi- 

 bular cartilages." This he regards as the homologue of the 

 chorda tympani. Pollard (49) also regards the R. mandibularis 

 internus as the chorda, and correctly homologizes it with the 

 R. alveolaris in Urodela. The other view of Froriep (22), 

 that the chorda is represented by a sensory branch to the 

 lower jaw similar to the R. ophthalmicus superficialis and 

 buccalis, i.e., a lateral line branch is certainly not correct. In 

 addition to the criticism made by Wiedersheim (Sy, p. 286), 

 the chorda in every way corresponds to the R. mandibularis 

 internus, as stated above, and not to the R. mandibularis 

 externus, which innervates lateral line organs. 



It is possible, however, if, as Kupffer (36) suggests, Froriep 

 really treats of epibranchial and not lateral ganglia, that he 

 had the correct nerve, but was mistaken in assigning it to the 

 lateral line system. 



In the IX + X the two outer ganglia on these nerves 



