— 91 — 



tains fibers otlier than lateralis ones, but whether they are all general cutaneous ones, or partly com- 

 munis, could not be determined. If they are all general cutaneous ones, Dactylopterus would resemble 

 Anieiurus (Herrick, 'Ol) in this respect, the communis fibers that form part of the raraus mandibularis 

 facialis in that fish all being distributed to regions external to the palato-quadrate. 



NERVUS ACUSTICU8. 



The nervus acusticus has, in sections of Scorpaena and Lepidotrigla, two roots, which enter 

 the tuberculum acusticuni close together, the slight swelling at their point of entrance lying im- 

 mediately ventral to the swelling for the lateralis nerves. The anterior root belongs to the anterior 

 division of the nervus, the posterior root to its posterior division. 



The anterior division, or ramus vestibularis, running forvvard sends, in my 55 mm Scorpaena, 

 two branches to the macula acustica sacculi. In the 63 mm Lepidotrigla, one of the two branches 

 that go to this organ has a separate origin from the medulla, between the anterior and posterior roots 

 of the nervus, the second branch arising from the posterior root. In both fishes, the ramus vestibularis 

 then sends a branch to the macula acustica utriculi, another branch to the crista acustica in the 

 ampulla of the external canal, and then ends in the crista acustica of the ampulla of the anterior 

 canal. All of these several branches separate distally into two parts, the two parts of the two 

 nerves that go to the ampullae supplying two separate and distinct organs in each of the ampuUae, 

 but the nerve that goes to the utriculus supplj'ing different parts, only, of the large and continuous 

 utricular macula. 



The posterior division of the nervus, or ramus cochlearis, runs backward and separates into 

 two parts one of which passes dorsal to the root of the glossopharyngeus and the other ventral to that 

 root. The dorsal branch supplies the two organs of the crista acustica in the ampulla of the posterior 

 canal, the ventral one supplying the two organs of the macula neglecta and also the papilla acustica 

 lagenae. The lagena is partially diffeientiated as a diverticulum arising from the dorsal surface of 

 the hind end of the sacculus. 



The papilla lagenae and the maculae sacculi and utriculi each have related otoliths. 



There was no indication of a ductus endolymphaticus in the dissections of Scorpaena, but in 

 sections, both of embryos and of the adult, a small remnant of the ductus is evident. In Trigla hirundo 

 the ductus is two or three times as large as in Scorpaena, being evident even in dissections. Retzius 

 ('81) shows the ductus in Trigla gurnardus. 



NERVUS GLOSSOPHARYNGEUS. 



The nervus glossopharyngeus of Scorpaena arises by a single apparent root, composed, as in 

 Menidia, of two bundles of fibers, a motor and a communis one. 



After issuing from the medulla the root runs at first posteriorly, then turns outward between 

 the dorsal and ventral branches of the ramus cochlearis acustici, and then forward and laterally to 

 its foramen, passing between the sacculus and the sinus utriculi posterior. At the bend in the root 

 there is an important collection of ganglion cells lying on the posterior aspect of the nerve, and from 

 this ganglion, in the adult, an intracranial communicating branch was found, going to the root of the 

 vagus. In the 55 mm specimen this branch could not be satisfactorily traced. In the 63 mm Lepi- 

 dotrigla two branches arise from the ganglion, one of which joins the root of the vagus, the other one 

 entering the intracranial vagus ganglion. The dorsal one of the two branches receives, on one side of 



