NERVUS FACIALIS OF ALBINO MOUSE 93 



by Kohnstam ('02) and has been described by Yagita and Ha- 

 yama ('09). Herrick ('16) calls it the nucleus salivatorius superior. 

 The efferent fibers of the great superficial petrosal nerve arise 

 from other cells in the same region (Yagita, '14). 



In the mouse, three distinct bundles of nerve fibers continue 

 the nervus intermedins peripheral to the ganglion. From the 

 anterior angle of the ganglion the great superficial petrosal nerve 

 emerges, while from its lateral angle two bundles of fibers pass 

 peripherally in a common sheath with the motor fibers of the 

 facial nerve. Before the genu is reached these bundles lie along 

 the antero-ventral side of the facial nerve, the smaller of the two 

 lying ventral to the larger (figs, 9 and 10, N.Ch.Ty., R.Cut.N.F.). 



In sagittal series medial to the genu these bundles are always 

 more or less separated by delicate connective tissue septa from 

 each other and from the motor fibers of the facial nerve. Beyond 

 the genu they lie along the lateral side of the nerve (fig. 10). In 

 this position the septum is not as distinct as it is nearer the gan- 

 glion. They are well separated in some series, while in others an 

 indentation along their medial side is all that indicates a division 

 into two parts. The ventral and smaller of these two bundles 

 becomes the chorda tympani, the dorsal and larger contains 

 fibers which are distributed to the skin of- the auricle and form a 

 nerve which I have called the ramus cutaneus facialis . 



With the exception of the efferent fibers of the great super- 

 ficial petrosal nerve, it was impossible in this material to tell 

 the exact relation of the fibers of the nervus intermedins to the 

 cells of the geniculate ganglion. That some of the fibers are 

 connected with the cells of the ganglion and others pass through 

 without interruption seems well established. 



Cutting the chorda tympani in the middle ear results in a 

 degeneration of about four-fifths of the cells of the geniculate 

 ganglion (Amabilino, '98; DeGaetani, '06). Nissl degeneration 

 of nerve cells in the brain stem after cutting the fibers to the 

 submaxillary and sublingual glands is proof that the chorda 

 tympani contains fibers which do not have their fibers in the 

 ganglion (Kohnstam, '02; Yagita and Hayama, '09). 



