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edge of the cartilaginous proötic bridge and then runs backward beneath that bridge to enter and 

 supply the rectus externus. In the adults both of Scorpaena and Trigla, the nerve perforates the 

 bony proötic bridge to reach its muscle. In Cottus octodecimospinosus it runs over the anterior edge 

 of the bony bridge. In small specimens of Dactylopterus it enters the trigemino-faciaUs Chamber 

 through the facialis foramen, and traversing that Chamber ventral to all the other nervous struc- 

 tures issues by the trigeminus opening of the chamber and then immediately enters its muscle. 



TRI CfEMINO-FA CIALIS COMPLEX. 



This complex has, in Scorpaena, five apparent roots, as Stannius has stated that it has in 

 Trigla, but two of these roots, the lateralis roots, may issue as a single root from the medulla and 

 then immediately separate. These two lateralis roots and the motor facialis root are so closely applied, 

 at their origin, that they appear almost as a single root, and are so shown in figure 28. In that figure, 

 furthermore, the communis root appears crowded down between the trigeminus and the lateralis 

 and motor facialis roots, this not being its position in sections of young specimens. 



My sections did not permit of more than a very general determination of the central origin 

 and peripheral distribution of the fibers of the several roots, but comparison with Menidia will show 

 that these determinations are probably correct. 



a. Roots and Ganglia of the Complex. 



The anterior one of the five roots of the complex is the so-calied root of the trigeminus, and 

 it contains both motor and general cutaneous fibers. The motor fibers lie on the dorso-mesial aspect 

 of the root as it emerges from the medulla. The fibers of the deep sensory root lie lateral to these 

 motor fibres, the two bundles of fibers extending dorso-mesially into the medulla, lying close together, 

 and certainly having their principal origins in groups of cells that represent respectively the chief 

 sensory and motor nuclei of the trigeminus. The remaining, ventral fibers of the root enter the 

 spinal V tract. The motor fibers, having issued from the medulla, soon cross, as in Menidia, to the 

 ventral surface of the root, and so continue during their intracranial course. The entire root, running 

 forward and laterally, lies at first, in sections, mesial to the other roots of the complex and then be- 

 tween the lateralis trigemini and lateralis facialis roots, ventral to the former and dorsal to the latter. 

 While still in the cranial cavity it gives off the profundus root. It then traverses the trigeminus 

 foramen, enters the trigemino-facialis chamber, and there immediately swells into the large trigem- 

 inus ganglion, which, in my young specimens, seems wholly distinct and separate from any other 

 portion of the ganglionic complex excepting only the large related sympathetic ganglion. The gang- 

 lion lies almost wholly in the trigemino-facialis chamber, a small coUection, only, of cells being found 

 on the ventral surface of the root just before it issues through its foramen; these cells being connected 

 with the main ganglion by a small ganglionic Strand which traverses the foramen. The ganglion 

 thus lies almost entirely in the cranial wall and not in the cranial cavity, all the other ganglia of the 

 complex, excepting only the related sympathetic ganglion, lying in the cranial cavity itself. 



The profundus root arises from the sensory portion of the trigeminus root, on its antero-mesial 

 aspect, and running antero-laterally enters the intracranial profundus ganglion which lies slightly 

 antero-mesial to the large stalk formed by the other roots of the complex. 



The next posterior root of the complex is the motor root of the facialis. This root emerges 

 from the medulla close to the anterior root of the nervus acusticus, almost as a part of that root, 



