92 D. A. EHINEHART 



Peripherally, the efferent root of the nervus intermedius 

 passes around the anterior border of the motor part of the facial 

 nerve, under the rest of the nervus intermedius, through the 

 medial border of the geniculate ganglion and into the great super- 

 ficial petrosal nerve. It is certain that only a few, if any, of its 

 fibers are connected with the cells of the geniculate ganglion. 

 This part of the ner\ais intermedius is present in all my series 

 and undoubtedly contributes efferent fibers to the great super- 

 ficial petrosal nerve. 



In the material used in this work it was impossible to tell what 

 proportion of the fibers of the nervus intermedius were medul- 

 lated and what non-medullated. All of the axis-cylinders are 

 small in diameter and the meduUated sheaths must be very 

 thin. Weigner ('05) has given an excellent description of the 

 fibers of the nervus intermedius of the ground-squirrel. In 

 teased preparations stained with osmic acid he found that most 

 of them are very fine with very delicate myelin sheaths (2 /x 

 in diameter), that a few are larger (5 fx), and that the nerve con- 

 tains nonmedullated fibers. The fibers of the nervus inter- 

 medius of the mouse are probably similar in size and character. 



Weigner describes numerous anastomoses between the ner\'Tis 

 intermedius, the vestibular nerve, and the facial nerve, which 

 are characterized by the presence of ganglion cells, scattered 

 and in groups, along the anastomosing bundles. These ganglion 

 cells, he states, are similar to those of the geniculate ganglion 

 and furnish additional centers of origin for nervus intermedius 

 fibers. In the mouse, no ganglion cells are present central to the 

 dorsal part of the ganglion and no true anastomoses were observed. 



That the afferent fibers of the nervus intermedius terminate in 

 the anterior extremity of the nucleus of the fasciculus solitarius 

 or a group of cells lying anterior to it seems well established. 

 All of the available papers dealing with this point in lower ver- 

 tebrates state this to be true. Van Gehuchten ('00) found this 

 to be the termination of these fibers in rabbits. The efferent 

 fibers to the submaxillary and sublingual glands arise from a 

 nucleus in the formatio reticularis at the level of the motor 

 facial nucleus. This nucleus was called the nucleus salivatorius 



