CUTANEOUS BRANCHES OF THE VAGUS. I15 



(= r. auricularis vagi), and indeed has predicted for fishes 

 just the arrangement which we have here ('95, p. 155): 

 "The question arises, then, as to what is the homologue 

 in lotver forms of the R. auricularis vagi of the tadpole. 

 I may here simply say that I believe that future investi- 

 gation will bring out more clearly a system of general 

 cutaneous branches in this region coexistent with the 

 lateral line nerves." 



Allis' account ('97, p. 689) of these nerves in Amia ob- 

 viously meets these conditions also, though he does not 

 S2em to have interpreted his facts in just this way. His 

 first branch, or r. supratemporalis, of the vagus has two 

 roots. One clearly comes from the nervus linese lateralis 

 and was traced to lateral line organs. The other arises 

 from an intra-cranial ganglion which corresponds perfectly 

 to our jugular ganglion. These fibres distribute to the 

 skin of the top of the head and the opercular region. 

 Allis repeatedly emphasizes the fact that this nerve dis- 

 tributes to regions where terminal buds abound, and, 

 though he is not explicit on this point, the inference is 

 that he regards it as wholly composed of communis fibres. 

 That it is largely so composed is probable from his de- 

 scription, but it is equally probable that some of these 

 fibres are of general cutaneous character and comprise the 

 r. cutaneous dorsalis. 



It is evident from the descriptions of Stannius and 

 Baudelot that the r. supratemporalis vagi (lateralis fibres) 

 and the proper r. cutaneous dorsalis vagi are in some 

 teleosts fused for the first part of their course, just as in 

 general we find both lateralis and general cutaneous fibres 

 in the analogous r. oticus. In the cyprinoids, for example 

 (Baudelot, '83, p. 133), we have this nerve arising by two 

 roots furnished with separate ganglia and giving rise to 

 opercular rami, anastomosis with r. recurrens V [VII] 

 (=r. lateralis accessorius) and doubtless also lateral line 

 organs, though the latter are not mentioned. 



Stannius describes (p. 85) an intra-cranial branch of the 

 vagus in several fishes which doubtless corresponds some- 

 times to the r. supratemporalis; yet as it contains, in some 



