CKAXIAL GANGLIA OF AMBLYSTOMA 



473 



the vagus lateral-line ganglion which has possibly been formed 

 by the ventral body-line primordium. The visceral trunk passes 

 from this gangUon to the region of a small blood vessel, alongside 

 of which it continues toward the posterior portion of the pharyn- 

 geal wall, where it is lost. Laterahs fibers also pass from this 

 ganglion down to the ventral body hne which is present for a 

 short distance in this individual. Very slender first and second 

 branchial trunks extend from the lower portion of the visceral 



Fig. 66 Frontal section, showing the small visceral ganglion of X on operated 

 side in front of which lies the IX lateral-line ganglion giving off fibers to occipital 

 group of sense organs. A similar level on normal side shows a large IX and X 

 ganglionic complex. The epibranchial placodes of IX and X were removed in 

 this individual, but the occipital and ventral body-line primordia were not re- 

 moved. X 37. 



Fig. 67 Frontal section of a specimen from which epibranchial and lateral- 

 line placodes of IX and X were removed, showing the X visceral ganglion and 

 visceral trunk of X issuing from its posteroventral portion. It contains no later- 

 alis fibers. X 37. 



ganglion into the second and third branchial arches, but do not 

 appear to carry any sensory fibers. The visceral ganglion of IX 

 emerges close to the root of VII from a root which lies at a lower 

 level than on the normal side. It gives off a trunk ventrally 

 which passes into the first branchial arch running along close to 

 a blood vessel for some distance until it is finally lost against the 

 branchial muscles of this arch. This specimen also gives no 

 evidence of containing visceral fibers in the sensory system. 



