CoGHiLL, Cranial Nerves of Tritofi. 263 



tomosis to the r. communicans IX-X ad VII. It seems necessary, 

 therefore, to emphasize the distinctness of these two structures. 

 Cole ('98) has stated clearly the ground for distinguishing between 

 them. The true Jacobson's anastomosis belongs to the communis 

 system and is distributed to the oral epithehum; while the r. 

 communicans sends fibers to the skin and must be considered as 

 a general cutaneous nerve, at least in the larger part. On the last 

 point Druner differs with me, since he considers this nerve as 

 motor. But whether it be general cutaneous or motor it should 

 not be confused with Jacobson's anastomosis. 



In Amblystoma, it is true, I found communis fibers in the r. 

 communicans. But in this case the communis fibers joined the r. 

 alveolaris and passed ventrad toward the floor of the mouth, so 

 that their distribution is clearly different from that of the fibers in 

 Jacobson's anastomosis. The two anastomoses between the 

 facialis on one hand and the glossopharyngeus and vagus on the 

 other exist side by side in both Amblystoma and Triton, and a 

 close study of these two structures here convinces me that the r. 

 communicans IX-X ad VII is in no way comparable to Jacobson's 

 anastomosis. 



As already mentioned, Druner holds that the r. communicans 

 is a motor nerve. I have been unable, however, to find any motor 

 fibers in it, either in Amblystoma or in Triton. The fibers which 

 may appear to go from it to the muscle depressor mandibulae 

 before the r. communicans reaches the r. jugularis are, in Triton 

 as well as in Amblystoma, clearly derived from the r. jugularis. 

 They pass caudad a variable distance in more or less close relation 

 with the r. communicans. On the other hand, as presented in my 

 description of this nerve, there is convincing evidence that the 

 nerve, is general cutaneous. And, being general cutaneous, it 

 belongs to the vagus, for the glossopharyngeus gets its general 

 cutaneous fibers from the vagus root. The term r. communicans 

 IX-X ad VII, or X ad VII is, then, a better expression of the actual 

 relations of the nerve. In Amblystoma I found that it belongs to 

 both the glossopharyngeus and vagus. In Triton, I believe it 

 belongs exclusively to the vagus. 



