Neeves, Spinal Coed, Beain and Otheb Ganglia 91 



and tensor palati muscles. The afferent fibers supply the whole of the 

 face, including the eyeball and conjunctiva ; and the mucous membrane of 

 the nose, cheek, tongue, tonsil, soft palate, the upper part of the pharynx 

 and the air-sinuses (antrum or maxillary sinus, mastoid sinus, etc.) ; and 

 the glands of the oral cavity. 



VI. The abducent nerve, (mixed) arises from a nucleus lying in the 

 floor of the upper part of the fourth ventricle close to the middle line. Its 

 fibers, both afferent and efferent, supply only the external rectus muscle 

 of the eye. 18 



VII. The facial nerve (mixed) is frequently described as a purely 

 efferent nerve, its afferent root being designated as the nervus intermedins 

 or 'nerve of Wrisberg '. The (afferent) fibers of the nervus intermedius 

 originate in the geniculate ganglion, and divide centrally into ascending 

 and descending branches, terminating in the column of gray matter in 

 which terminate the fibers of the ninth and tenth nerves. Peripherally, 

 the afferent fibers are probably supplied to the sides and base of the 

 tongue, connecting with the gustatory receptors. 



The efferent fibers of the facial nerve arise from a nucleus lying 

 posterior to the superior olive, at some depth below the floor of the 

 fourth ventricle, and are distributed peripherally to the muscles of the 

 face, the muscles of the soft palate (particularly the azygos uvulae and the 

 levator palatini) , the buccinator and the platysma myodes. 



VIII. The auditory nerve (afferent) joins the medulla close to the 

 outside of the seventh nerve. The nerve is composed of axons of bipolar 

 cells in the cochlea (on the cochlear branch) and in the vestibule of the 

 ear (on the vestibular branch). On entering the medulla, the axons 

 from the cochlear division branch, the ascending branches terminating in 

 the ' ventral ' or ' accessory ' nucleus, and the descending branches in the 

 'dorsal' or 'principal' nucleus (acoustic tubercle). From the nuclei 

 new relays of axons cross upwards to the opposite sides of the medulla 

 and run upwards in the lateral fillets, some being relayed in the superior 

 olivary nucleus, and all terminating in the posterior corpora quadri- 

 gemina (and internal geniculate bodies?). 



The fibers of the vestibular division of the eighth nerve also send their 

 branches into the ' ventral ' and ' dorsal ' nuclei, the fibers, or at least 

 many of them, running through the nuclei into the cerebellum, where they 

 connect with cells in the ' roof ' nucleus. 



18 The nuclei of the third, fourth, and sixth nerves receive collateral fibers ('com- 

 missural ') from the posterior longitudinal bundle, many of which are axons from 

 cells in ' Deiter's nucleus '. By means of these commissural fibers, doubtless, the 

 actions of the various eye muscles are coordinated. 



