194 



NERVE COMPONENTS OF BONY FISHES. 



stated that the n. oticus innervates two "instead of three 

 organs of the infra-orbital line. 



The nerve which I have termed the otic evidently cor- 

 responds to the r. oticus + the external buccal of Gadus, 

 as described by Cole ('98a). 



Wright ('85, p. 491) holds with Van Wijhe that the r. 

 oticus should be defined as the nerve of the neuromasts 

 contained within the sqiiamosal bone. In this case the 

 term should be confined to only one of the twigs here 

 described. 



It is, I think, sound morphology to regard the r. oticus 

 as the proper dorsal branch of the facialis segment. The 

 sensory portion of the dorsal rami was primitively of 

 general cutaneous nature without doubt. The morpho- 

 logical character of this nerve is therefore given to it by 

 its general cutaneous rather than by its lateralis fibres 

 and the latter accompany the former to their peripheral 

 distribution secondarily and as a matter of mechanical 

 convenience, just as the lateralis fibres of the r. supra- 

 temporalis vagi or glossopharyngei may (or may not) 

 accompany the general cutaneous fibres of the dorsal 

 ramus of the corresponding segment and just as the r, 

 ophthalmicus superficialis VII may accompany the corre- 

 sponding trigeminal nerve. This conception is justified, 

 further, by the known relations of the r. oticus to the 

 spiracle in forms which possess the latter structure 

 (Wright, '85, Mliller, '97, AUis, '97 and others). Pollard, 

 ('91) finds that the r. oticus in Clarias and Auchenaspis 

 also possess both a lateralis branch and a branch to the 

 skin which does not go to any lateral line organ. 



The r. oticus, then, was probably originally the dorsal 

 ramus of the facial nerve to which lateralis elements have 

 secondarily been added and whose general cutaneous 

 portion has, like that of the profundus nerve, been ceno- 

 getically fused with the Gasserian ganglion. Compare 

 the discussion of metamerism in Section 12, 



