154 KERVE COMPONENTS OF BONY FISHES. 



mandibular canal organ. Then under the origin of the 

 m. intermandibularis the trunk divides into two nearly 

 equal portions of which the dorsal one contains all of the 

 coarse, i. e.^ facialis fibres. These supply the second and 

 first mandibular canal organs, the remaining or trigeminus 

 fibres supply the skin of the tip of the mandible and the 

 middle portion (not the edges) of the lower lip. 



5. — Comparative Review of the Hyomandibiilaris. 



The truncus hyomandibularis receives fibres belonging 

 to the viscero-motor and the three sensory components. 

 The general cutaneous component is very small. In Lota 

 and Esox (Goronowitsch, '96) the same relations prevail, 

 though in Lota (p. 28 and Fig. 12) the general cutaneous 

 portion is very large and passes off from the Gasserian 

 ganglion as a broad anastomosing band. It would be in- 

 teresting to learn the exact distribution of these trigeminal 

 fibres in Lota. 



i. — The opercular rami. — The muscles supplied by the 

 r. opercularis profundus are undoubtedly to be compared 

 with the general constrictor system of the facial region of 

 selachians. The lateralis fibres in the r. opercularis 

 superficialis have been already discussed. The general 

 cutaneous portion of this nerve is, I believe, peculiar to 

 the teleosts. It is of the same nature as the cutaneous 

 portion of the r. hyoideus. 



ii. — The ramus hyoideus. — This nerve is usually de- 

 scribed as a pure motor nerve, and such it probably is in 

 most vertebrates other than the bony fishes. The mus- 

 cles supplied in Menidia (hyo-hyoideus) evidently belong 

 to the constrictor system of the facialis segment and no 

 other. 



All of the ofeneral cutaneous fibres which enter the 



