156 STRONG. [Vol. X. 



system of general cutaneous branches in this region coexistent 

 with the lateral-line nerves. I have noticed in certain descrip- 

 tions that dorsal branches are described which the investigator 

 has been unable to trace to lateral sense-organs. Furthermore, 

 Shore (56), in his work on the vagus nerve in Selachians, has 

 described a dorsal cutaneous branch of medium fibres. 



Ewart (18) also mentions a dorsal branch from the Glosso- 

 pharyngeus, immediately beyond its ganglion, which passes 

 upwards through the cranium to reach the skin over the audi- 

 tory region, and "which apparently does not assist in supplying 

 either mucous canals or sensory tubes." We have, in addition 

 to this, one or two branches which separate from the lateral 

 nerve before its exit from the cranium to supply the aural and 

 part of the occipital mucous-canals, and which are homologous 

 with the minute twig from the lateral-line root in the tadpole 

 {8). Ewart and Mitchell further state (19): ''The lateralis 

 nerve behind the first branchial cleft consists entirely of special 

 sensory, somatic fibres ; in front it seems to be accompanied by 

 a few ordinary, sensory fibres, which reach the skin." 



It is possible that the R. meningeus and R. tympanicus in 

 human anatomy are also represented by some of these general 

 cutaneous branches in the tadpole, the R. tympanicus possibly 

 being represented by the R. communicans ad facialem. 



A further inference may be made respecting the ganglia. It 

 has been seen above that the ganglionated portion of these gen- 

 eral cutaneous nerves lies in the most proximal ganglion (gan- 

 glion A). It would follow from this and from what has gone 

 before that this ganglion, or ganglia, would represent, in part 

 at least, the two proximal, or jugular, ganglia^ of the IX + X. 

 This conclusion seems to be similar to Shore's from his study 

 of Selachians (55 and 56). 



By a comparison of the tadpole with the higher vertebrates 

 it would seem that there is a considerably larger supply of 

 these general cutaneous fibres, relatively, in the former than in 

 the latter. This is readily accounted for, I believe, by consider- 



1 There appears to be some confusion in the nomenclature of these ganglia in 

 the text-books of human anatomy. It is not necessary to enter into this here, 

 however, and there need be no confusion if it is understood that the two proximal 

 ganglia on the IX + X are meant. 



