88 D. A. RHINEHART . 



SENSORY PART OF THE NERVUS FACIALIS 



1. Ganglion geniculi 



The geniculate ganglion in the mouse is divided into two por- 

 tions continuous with each other anterior to the facial nerve. 

 The larger, the main part of the ganglion (fig. 3, G.Gen.) is 

 located half way between the superficial origin of the facial 

 nerve and the genu externum. It is elongated triangular in 

 shape, the long axis extending anteriorly and ventrally. The 

 anterodorsal surface is separated from the cerebrum by the 

 cranial wall, the tip of the ganglion extending through the hiatus 

 canalis facialis as far as the posterior extremity of the semilunar 

 ganglion. The postero-ventral surface is separated by the bone 

 from the cochlea posteriorly and the tensor tympani muscle 

 anteriorly. The posterodorsal border of the ganglion is in rela- 

 tion to the anterior border of the motor part of the facial nerve. 



The fibers of the nervus intermedins leave the ganglion at its 

 medial angle, those fibers of the nervus intermedins which pass 

 peripherally in the facial nerve emerge at the lateral angle, and 

 from its anterior angle the great superficial petrosal nerve takes 

 origin. 



The above description corresponds closely to that of Penzo 

 ('93) and Weigner ('05) except that the ganglion is not located 

 at the genu, but medial to it. 



The dorsal and smaller part of the geniculate ganglion (figs. 

 2 and 3, G.Gen.d.) is placed dorsal and medial to the main por- 

 tion. It is located in a triangular interval between the motor 

 part of the facial nerve ventrally, the vestibular ganglion dorsally 

 and the cranial wall anteriorly. It is separated by .a thin layer 

 of connective tissue from the vestibular ganglion and is inti- 

 mately related to the nervus intermedins. It is possible that 

 this part of the ganglion in the mouse represents the numerous 

 scattered ganglion cells along the nervus intermedins described 

 by Weigner ('05) in the ground-squirrel. 



The cells of the geniculate ganglion are approximately half 

 the size of those of the semilunar and dorsal root ganglia. They 

 are mostly of uniform size with only a few larger and smaller 



