Herrick, Cranial Nerves of the Cod Fish. 283 



to enter the lower jaw. In this region we find scattered through 

 the more deeply staining general cutaneous fibers strands of 

 very fine and more feebly staining nerves. These I take to be 

 the communis fibers. 



Having reached the mandible, a large branch is given off 

 ventrad, which divides into two parts, an inner and an outer. 

 The latter runs down external to the bones of the mandible to 

 supply the overlying skin. The inner part runs down internal 

 to all of the bones of the mandible and to the r. mandibularis 

 externus VII, sends a twig caudad and another one cephalad 

 along the dorsal border of that nerve and then enters the man- 

 dibular lateral line canal from its inner face through the same 

 foramen as the lateralis twig for the sixth canal organ and sup- 

 plies the skin of the ventral edge of the mandible in this region. 

 The little twig of fine fibers which accompanies the r. mandi- 

 bularis externus cephalad is joined still farther cephalad by 

 motor fibers from the r. mandibularis V, as described below, 

 and the mixed nerve thus formed runs into the isthmus to sup- 

 ply its skin and the m. genio-hyoideus. The twig which ac- 

 companies the r. mandibularis caudad is exceedingly minute. 

 It runs back to the articulation of the mandible with the quad- 

 rate and then turns turns inward to supply the mucosa covering 

 the articular and quadrate bones internally. 



This twig is so closely applied to the r. mandibularis ex- 

 ternus VII that the dissector relying upon gross methods only 

 would almost infallibly consider that it takes its origin from this 

 nerve. Nevertheless it preserves its individuality perfectly in 

 the sections. No fibers could be traced from the r. mandibu- 

 laris VII to the mucous lining of the mandible, though this 

 nerve runs for a long distance in the earlier part of its course 

 in the mandible immediately under this mucosa and careful 

 search was made for such fibers. It is probable that the whole 

 mucous lining of the hyoid and suspensory structures is inner- 

 vated from the trigeminus. 



The r. mandibularis V now runs forward along the outer 

 face of the mandible parallel with the dorsal edge of the artic- 

 ular bone, and later along the inner face of the latter between 



