122 D. A. RHINEHART 



From the most posterior part of the convexity of the facial 

 nerve, and just distal to the anastomosis with the ramus auric- 

 cularis vagi there arise from the motor part of the facial nerve 

 two small motor nerves which are distributed to the posterior 

 belly of the digastric and the stylohyoid muscles (figs. 11, 12, and 

 13G, N. to D,ia., and N. to Sty-hy.). 



SUMMARY AND CONCLUSIONS 



The facial nerve of the mouse corresponds very closely to that 

 of other mammals and man, and more closely resembles the glosso- 

 pharyngeal than any of the other cranial nerves. It consists of 

 two parts: one part made up of those fibers which arise in the 

 motor nucleus and form the motor part of the nerve, the other 

 part being formed by the nervus intermedins and its peripheral 

 continuation. 



The motor part of the facial nerve supplies the stapedius, the 

 stylohyoid, the posterior belly of the digastric, the auricular 

 muscles, and the superficial muscles of' the face including those of 

 the vibrissae (special visceral efferent component; Herrick, '16, p. 

 146). 



The nervus intermedins is composed of afferent fibers having 

 their cell bodies in the ganglion geniculi, and efferent fibers 

 which have no connection with the cells of the ganglion. The 

 ganglion itself is of the cerebrospinal type of ganglia and is 

 composed of unipolar ganglion cells. 



The nervus intermedins has three branches, the great super- 

 ficial petrosal nerve, the chorda tympani, and the ramus cutaneus 

 facialis. The first two contain both afferent and efferent fibers 

 the third is composed entirely of afferent fibers. The efferent 

 fibers which enter the great superficial petrosal nerve form a 

 separate efferent root of the nervus intermedins. 



The great superficial petrosal nerve enters the sphenopalatine 

 ganglion. Sympathetic fibers from the superior cervical sympa- 

 thetic ganglion reach the sphenopalatine ganglion by way of the 

 deep petrosal nerve and the nerve of the pterygoid canal, and 

 through the nervus abducens. Because the termination of these 

 fibers in the sphenopalatine ganglion has not been determined, 

 the function of each set of fibers is uncertain. 



