— 88 — " 



ginal subdivisions of the root and center have been lost. The equally evident assumption that all 

 the lateralis fibers associated with trigeminus nerves are trigeminus ones cenogenetically fused with 

 the lateralis fibers of the facialis segment, is not made; and yet this assumption has apparentlv much 

 more evidence in fact, for the lateralis trigemini and lateralis facialis fibers here, and in many other 

 fishes also, arise by separate apparent roots and each have an independent ganglion. Johnston, in 

 a recent work ('05 a, p. 222), does make what is practically the equivalent of this assumption, for 

 he there says that it seems probable to him that the supraorbital, infraorbital and hyomandibular 

 latero-sensory lines belong respectively to the profundus, trigeminus and facialis segments. He does 

 not, however, say that the nerves innervating the three lines must also belong to those same Seg- 

 ments, and such may not be his meaning. 



One other point relating to this same subject can here be mentioned. In many teleosts, as 

 already stated, a Strand of general cutaneous fibers, arising from the Gasserian ganglion, joins the 

 truncus hyoideo-mandibularis facialis. These fibers join that nerve extracranially in Scorpaena, 

 Menidia and many other fishes, but intracranially in Pleuronectes (Cole & Johnstone, 'Ol, p. 124). 

 Here then is another instance in which the cenogenetic fusion of fibers belonging originally to the 

 trigeminus and facialis segments might be suggested, but neither Herrick nor Johnston ('05 a) even in- 

 timate it; and yet, in Amia, Kingsbury ('97), before the publication of Herrick's work, had stated that 

 general cutaneous fibers issue from the brain in the root of the facialis in all the specimens of that 

 fish that he had examined, and Johnston ('05 b), since the publication of Herrick's work, says that 

 they also issue in that root in Petromyzon. 



And if the assumption of cenogenetic fusions can be made either for the general cutaneous 

 or lateralis fibers of the coniplex, why can it not also be made for the communis fibers? Those fibers 

 then would, in large part at least, normally belong to the nerves with which they are associated, 

 certain juxtapositions perhaps being possible where there are no skeletal Clements to prevent them; 

 and the varying quantity of communis fibers in the several trigeminus and facialis nerves would 

 be due to a corresponding Variation in the development of the terminal organs innervated by either nerve. 



Eeturning now to the descriptions, the buccalis facialis traverses, in all the fishes examined, 

 the trigeminus ganglion, and, accompanying the ramus maxillaris trigemini, supplies the organs of 

 the post- and siib-orbital portions of the main infraorbital canal. 



The truncus facialis, in Scorpaena, Lepidotrigla and Dactylopterus contains motor, lateralis 

 and communis fibers, the latter fibers, in all these fishes, traversing the facialis foramen and joining 

 the other fibers of the truncus either as they are traversing, or after they have traversed the same 

 foramen. 



The ramus palatinus contains communis fibers only, and in Scorpaena it usually has an inde- 

 pendent origin from the communis ganglion. In the 55 mm Scorpaena, it had such an origin on one 

 side of the head, while on the other side it arose from the base of the bündle of communis fibers sent 

 to the trigeminus ganglion. Turning downward in the cranial cavity, the nerve traverses the palatine 

 eanal in the proötic, enters the myodome, and, turning forward, enters the orbit along its floor; its 

 further course not being traced. In Cottus, the palatinus has a course similar to that in Scorpaena, 

 but in Trigla, Lepidotrigla and Dactylopterus it does not separate from the other communis fibers 

 until after those fibers have traversed the facialis foramen. There it turns forward and downward 

 along the floor of the trigemino-facialis Chamber, issues through the trigeminus opening of that 

 Chamber, and, traversing the myodome of the fish, enters the orbit. 



