— 92 ~ 



the specimen, but not on the other, a relatively important branch from the dorsal branch of the ramus 

 cochlearis acustici. 



Having traversed its foramen the nerve turns forward along the outer surface of the skull and 

 swells into an elongated ganglion, which has a sympathetic ganglion associated with it. From this 

 ganglion two nerves arise. One of these nerves is the ramus anterior of the nervus, which, running 

 forward, anastonioses with the communis branch from the facialis to form Jacobson's nerve, as al- 

 ready described. The other branch is the ramus posterior of the nervus and was not further traced. 



NERVUS VAGUS, 

 a. Nervus lineae lateralis vagi. 

 The root of the nervus lineae lateralis vagi issues from the tuberculum acusticum directly dorsal 

 and slightly posterior to the root of the glossopharyngeus. In the 63 mm Lepidotrigla it arises by two 

 roots, a small anterior and a large posterior one. It runs posteriorly in the cranial cavity and issues 

 through the vagus foramen, there lying directly upon the dorsal surface of the root of the vagus. 

 A supratemporal branch is immediately given off, and running upward innervates the latero-sensory 

 Organs of the supratemporal commissure and also those of the extrascapular and suprascapular sec- 

 tions of the main infraorbital canal; this branch having a separate extracranial ganglion. The main 

 nerve then enters its own ganglion, and was not further traced. No ganglion cells are found in the 

 main nerve before it issues from the cranial cavity, and there is no branch of t"he nerve accompanying 

 the nervus glossopharyngeus. 



b. Nervus Vagus. 



The roots of this nerve could only be properly traced in the 63 mm Lepidotrigla. In this fish, 

 and also in the small specimens of Scorpaena and Dactylopterus, three small rootlets arise from the 

 meduUa anterior to the main root of the nervus. These rootlets, in Lepidotrigla, arise one anterior 

 to the other, in the line of the main root, at intervals of about 80 \i. They pierce what is apparently 

 a two layered cranial membrane, richly supplied with blood vessels, the anterior rootlet then joining 

 the main vagus root, while the other two traverse the intracranial vagus ganglion, as will be later 

 described. The anterior rootlet seems to be a purely motor one, the other two apparently containing 

 communis fibers only; but of these determinations I am not at all certain. 



The main root of the nervus contains motor, communis and general cutaneous fibers, most of 

 these latter fibers arising from the spinal V tract while sonie seem to have a superficial origin, Coming 

 down from above. The three bundles issue from the medulla, in Lepidotrigla, close together, as a 

 Single large stalk which is joined by the anterior one of the three anterior rootlets, and also by one of 

 the two communicating branches from the intracranial ganglion at the bend in the root of the glosso- 

 pharyngeus. On or in connection with the general cutaneous portion of the root, an important intra- 

 cranial ganglion is formed, and this ganglion is joined by one of the branches from the glossopharyn- 

 geus and is traversed by two of the anterior rootlets of the vagus itself. From the ganglion a stout 

 intracranial branch is sent upward in the cranial cavity and issues on the dorsal surface of the skull 

 near its bind end, this nerve apparently receiving all its fibers from the two anterior rootlets of the 

 vagus, and the nerve accordingly quite probably being largely if not entirely of communis origin. 

 In the sections of Lepidotrigla it could not be determined whether or not this nerve anastomosed 

 with the recurrent component that accompanies that branch of the lateralis facialis that innervates 



