RAMUS OPERCULARIS PROFUNDUS VII. 137 



ease, for its fibres do not mingle with the other fine fibres, 

 but are separated by the coarse lateralis and motor fibres 

 from the communis bundle. 



/. — TJie Ramus Opercularis Profundus VII. 



The motor component of the truncus hyomandibularis 

 can be followed, in spite of its intimate relations with the 

 lateralis fibres, up to the point where the truncus hyo- 

 mandibularis begins to turn ventrad (515). Here it 

 divides into three parts, one part leaving the main nerve 

 dorsally to turn immediately caudad, another continuing 

 cephalad after the truncus has turned ventrad, while the 

 third follows the truncus in its farther course. The first 

 two parts I include under the term r. opercularis pro- 

 fundus VII. 



The dorsal branch, which is the r. opercularis of Stan- 

 nius, supplies three muscles. It passes directly caudad 

 just dorsally of the apex of the narrow slit-like extension 

 of the pharyngeal cavity which runs up between the 

 pseudobranch and the first gill. It then passes through 

 the dorsal end of the m. adductor hyomandibularis from 

 its mesal to its lateral face, meantime contributing a few 

 fibres for the innervation of this muscle {m. ad. hy., Fig. 

 4). The nerve continues caudad along the outer face of 

 this muscle to its end, and then farther caudad between 

 the m. adductor operculi and the m. levator operculi, 

 where it divides, the ventral twig supplying the m. ad- 

 ductor operculi (;;/. ad. op.). The remaining fibres con- 

 tinue caudad and almost immediately cross the course of 

 the r. opercularis vagi. The two nerves lie almost in 

 contact for a short distance, but clearly do not anastomose, 

 as is the case in the carp (Baudelot, '?>t„ p. 132, and Stan- 

 nius, '49, p. 61) and Lophius (Guitel, '91), A little farther 



