146 NERVE COMPONENTS OF BONY FISHES. 



Allis ('97, p. 632) in Gadus and Esox, and all of these 

 may represent the gular line of Chlamydoselachus (Gar- 

 man, '88). 



The r. mandibularis VII after giving off its first branch, 

 as just described, runs along the outer face of the hyo- 

 mandibular bone. In this part of its course it contains 

 chiefly very coarse lateralis fibres, with a small bundle of 

 fine communis fibres along its inner face. At the extreme 

 cephalic tip of the hyomandibular bone (500) the fine 

 fibres separate mesally and dorsally from the coarse ones 

 and a strong fascia in which portions of the m. adductor 

 mandibulae are inserted, passes between the two divisions, 

 which become widely separated. The fibres of the more 

 lateral bundle are very large with few medium ones and a 

 very few small ones intermingled ; those of the mesal 

 bundle are mostly very small with a considerable number 

 of medium-sized and more heavily myelinated fibres in- 

 termingled. These bundles represent the r. mandibularis 

 externus and the r. mandibularis internus of the facial 

 nerve. 



From the lateral bundle the second branch is given off 

 at 488 [m. VII. 2), which descends along the inner face 

 of the preopercular bone, running slightly caudad, to enter 

 the opercular canal and finally to supply its fourth canal 

 organ. 



The third branch arises from the fine-fibred communis 

 bundle at 483 {m. VII. j), runs ventrad and caudad 

 and somewhat further mesad than the last. Having 

 reached the mucous lining of the pharyngeal cavity just 

 dorsally of the epihyal bone, it divides into two branches, 

 directed cephalad and caudad respectively. The former 

 runs under and innervates the mucous membrane cover- 

 ing the dorsal surface of the bones of the hyoid arch as 



