Herrick, Cranial Nerves of Ambly stoma. 199 



same position as the ramus hyo-mandibularis, but further dor- 

 sad and laterad. It may be called — following von Plessen and 

 Rabinovicz — the accessory ramus hyo-mandibularis (h. m.). In 

 its peripheral distribution this ramus accords more perfectly 

 with the hyo-mandibularis of these authors. Its identification 

 with the accessory ramus is based upon its central relations ; on 

 the one hand it does not receive the ramus communicans from 

 the glossopharyngeus, and on the other hand it emerges in 

 company with the ramus buccalis. Shortly after entering the 

 lower jaw it effects an anastomosis with the ramus mandibularis 

 trigemini (c. Jim.) and then continues forward to the tip of the 

 chin in two branches lying close under the skin of the side of 

 the face. 



The ramus buccalis (buc.) separate farther cephalad than 

 any of the other rami of the facialis complex. Upon separ- 

 ating from the last mentioned it also enters the lower jaw and 

 passes forward along the ectal aspect of the jaw bone, between 

 the dentary and the skin. This course it maintains up to the 

 tip of the lower jaw, where most of its fibres are given up to 

 the skin. Strong describes a ganglion in Amblystoma in about 

 the proper position- to correspond with the buccal ganglion of 

 Salamandra as figured by von Plessen and Rabinovicz. Our 

 specimens may have been older than both of the others referred 

 to. In any'case they show no trace of such a ganglion, though 

 occasional ganglion cells are found far out in the main lateral 

 trunk of the facial. The fibres of the ramus buccalis are mainly 

 if not wholly derived from the dorsal root, as Strong has 

 pointed out. The nerve which I have called the accessory hyo- 

 mandibular seems to be the same as Strong's "small branch to 

 lower jaw " which he derives from the fasciculus communis and 

 considers the representative of the chorda tympani of higher 

 forms. The anastomosis of this branch with the r. mandibu- 

 laris of the fifth in Amblystoma would serve to strengthen this 

 homology. 



The various elements of the facial nerve are in this type so 

 completely separated in their peripheral courses that their exact 



