CRANIAL GANGLIA OF AMBLYSTOMA 



485 



The gasserian ganglion is slightly smaller than on the normal side 

 and lies somewhat separated from the ophthalmic ganglion. The 

 visceral portion of VII is a little smaller and no definite alveolar 

 nerve can be found. The special visceral or palatinus VII is 

 present (fig. 86). 



Fig. 87 Frontal section of a specimen killed three days after removal of crest, 

 cells over the branchial region, showing lateral-line placodes of IX and X forming 

 ganglia. Between them in ectoderm lies the epibranchial placode of X. On the 

 normal side lies a group of crest cells near the epibranchial placode of X, possibly 

 forming a portion of visceral ganglion of X. X 37. 



Fig. 88 Portion of a frontal section in a specimen killed a few days after re- 

 moval of crest cells, showing normal epibranchial placodes of IX and X. X 37. 



Fig. 89 Showing a large vagus lateral-line ganglion and ramus lateralis supe- 

 rior vagi in a specimen killed eleven days after an attempt had been made to 

 remove all crest cells on right side. X 37. 



Fig. 90 Showing in the same specimen the IX visceral ganglion. X 37. 



h. Contribution to IX and X. A specimen killed three days 

 after operation shows on the operated side a large lateral-line 

 ganglion placode of IX just anterior to the epibranchial placode 

 of X (fig. 87). On the anterior surface of the large vagus lateral- 

 line placode are a number of loose placodal cells given off from 

 the placode. No crest cells are found in the branchial region of 

 the operated side. • On the normal side anterior to the vagus 



