CoGHiLL, Cranial Nerves of Anibly stoma. 257 



branch." Now, the r. palatinus should pass near the ventral 

 surface of the Gasserian ganghon, and any part of the facialis 

 associated with the dorsal surface of this ganglion must be the 

 anterior division of the lateralis VII root. 



If this nerve which Fish thus describes is the r. palatinus 

 VII, as his drawings seem to indicate, the lateralis VII root 

 would seem to be absent in adult Desmognathus. In the adult 

 of Amblystoma, however, there is no apparent diminution of 

 this root or its ganglia. Neither does Gage ('93) find any 

 reduction of the nerve in adult Diemyctylus. In the adult of 

 Triton, on the other hand (Drunek, '01, p. 573), there is no 

 degeneration of the ganglion of the anterior division of the 

 lateralis VII root, while the ganglion of the posterior division 

 disintegrates upon metamorphosis. Again in the adult of 

 Salamandra (Druner, '01, p. 538) both of the lateralis VII 

 ganglia undergo degeneration. In Urodela, therefore, arrested 

 phylogenetic stages may be observed in a process which is 

 complete in the life history of Anura. 



So far as the roots and ganglia of the fifth and seventh 

 nerves of Anura are adequately known, their most important 

 differences from those of Urodela are in regard to the relative 

 positions of their ganglia, and in regard to the origin of the 

 communis VII root. 



The communis root in Rana (Strong, '95) emerges ven- 

 trally of the acustic root. This separation of the communis 

 VII from the motor VII root is still more marked in Menidia 

 and Gadus (Herrick, '99, '00) where the communis root 

 emerges between the lateralis roots. This fact indicates that 

 the difference between Anura and Urodela in this particular 

 cannot be due to correlative changes in the lateralis VII and 

 acustic roots in Rana, as Strong suggests ('95, p. 1 14). 



The ganglia of the facialis and trigeminus of Anura are 

 fused into a single ganglionic complex while they form two dis- 

 tinct complexes in Urodela. That this difference can be in any 

 way correlated with differences in the peripheral relation of the 

 rami, such as the r. alveolaris and r. mandibularis internus, or 

 with differences in the manner of origin of the communis root 



