Nos. IAND2.J .^X ATOMY OF SCOMBER SCOMBER. 267 



reaches the dorso-lateral surface of the adductor operculi, which 

 muscle it innervates. Continuing backward and downward, 

 between the adductor operculi and the levator operculi, and 

 then along the internal surface of the latter muscle, it sends 

 one branch to this muscle, apparently innervating it. Beyond 

 the hind edge of the levator operculi it reaches the inner 

 surface of the operculum, where it breaks up into several 

 branches, one of which goes to the dorsal patch of degenerate 

 muscle fibers near the hind edge of the operculum, and an- 

 other to the next ventral patch. These two branches of the 

 truncus thus innervate the adductor hyomandibularis, the ad- 

 ductor arcus palatini, and the adductor operculi, and apparently 

 also two patches of degenerate muscle tissue on the inner sur- 

 face of the gill cover, and the levator operculi. The two branches, 

 taken together, are, accordingly, the homologue of the single ramus 

 opercularis facialis of Aiiiia. By Stannius the first of these two 

 branches, in Scomber, is called the ramus ad musculum adduc- 

 torum arcus palatini, the second branch, only, being considered as 

 the ramus opercularis. 



Opposite or beyond these two branches the truncus facialis is 

 joined by the commissural branch from the truncus maxillaris tri- 

 gemini, this branch running dorsal to the truncus facialis, and there 

 usually separating into two parts, both of which join the truncus 

 near its posterior edge. In the specimen examined by Mr. Nomura 

 a small branch was sent from this commissural nerve backward to 

 one of the sympathetic ganglia that are found related to the nervus 

 glossopharyngeus. This commissural branch of Scomber is ap- 

 parently, as already stated, the homologue of the one described 

 by Goronowitsch in Lota, in which fish it is said by him to arise 

 from the trigeminus I., and to probably contain motor fibers 

 destined for the truncus facialis. In Aiiiia it is not found ; and 

 Herrick does not mention it in Mcnidia. By Stannius it is said 

 to be found in nearly all teleosts. In Chimccra Cole describes 

 a short commissural connection between the so-called root of the 

 buccal of that fish and the root of the hyomandibularis, which 

 may, possibly, though it seems to me not probabl\', be this nerve. 



Beyond this commissural branch, the truncus, in Scomber, en- 

 ters the -facial canal in the hvomandibular, and while still in that 



