546 'Journal of Comparative Neurology and Psychology. 



have yet to find an instance in Amphiuma where the two do not 

 emerge from the ganghon separate from each other. In Ambly- 

 stoma (Coghill) the r. communicans is composed of general 

 cutaneous and communis fibers; in Spelerpes (Bowers) of general 

 cutaneous fibers only, apparently. Druner assumes that in the 

 Urodela in general the anastomosis contains motor fibers. For 

 example, in Amblystoma and Triton he describes (1901 and 1904) 

 a motor component in the anastomosis X ad VII, but Coghill 

 (1906) can find no evidence of motor fibers in the anastomosis 

 in these forms. In Amphiuma Druner believes the anastomosis 

 to consist solely of motor fibers, but I can find nothing to support 

 such an opinion. Beyond question Druner is correct in figuring 

 the r. communicans as giving off" fibers to branches of the jugularis 

 VII, but it is not necessary to draw his conclusion that these are 

 motor fibers. In Amphiuma the r. communicans consists chiefly, 

 if not wholly, of general cutaneous fibers. In serial cross-sections 

 these can be followed with precision from the second IX-X root 

 into the ganglion, thence out into the anastomosis. I have not been 

 able to demonstrate with certainty that no communis fibers pass 

 from the first IX-X root into the r. communicans. Such fibers pass 

 very close to the beginning of th^ latter, and possibly some enter. 

 That none of the coarse deeply staining motor fibers of the first 

 IX-X root enter the anastomosis seems certain. As the anastom- 

 sis approaches thi VII nerve it is seen to divide into a dorsal and 

 a ventral branch (figs. 9, 9a, 14-16, 18 and 21). These two 

 branches unite with branches of the r. jugularis that innervate 

 the sphincter colli and interhyoideus muscles. The variability 

 in the mode of union is shown in figs. 14-18. In some cases (fig. 

 17) the r. communicans does not divide on approaching the r. 

 jugularis. Fischer noticed the double nature of the anterior 

 end of the r. communicans and designated the dorsal portion as 

 "Kopftheil des Sympathicus." Druner also describes a dorsal 

 smaller portion that passes ventrally into the r. jugularis. In 

 Amblystoma (Siredon) he recognizes a sensory component in the 

 r. communicans, and suggests the possibility of some of the fibers 

 being sympathetic. 



In Amphiuma motor branches from the facial nerve commonly 

 run posteriorly into the anterior portion of the depressor mandibulae 

 muscle closely joined with the dorsal branch of the anastomosis. 

 When these branches are finally distributed to the muscle there 



