1 92 STRONG. [Vol. X. 



ally from the lobus trigemini. Finally, we have in Acipenser 

 (Goronowitsch, 28), as seen above, both roots present, i.e., a 

 fine-fibred most dorsal root from the lobus trigemini,, and 

 another fine-fibred root emerging ventrally with the motor root 

 of the VII. 



The accounts of the R. palatinus also seem to vary. Accord- 

 ing to Stannius, it is sometimes given off by the V, sometimes 

 by the VII, and sometimes is independent. It is sometimes 

 reenforced by a branch from the IX (Stannius, Goronowitsch), 

 and by Pollard (49), in Polypterus, is described as composed of 

 united branches from the V, VII, and IX nerves. Goronowitsch 

 denies the existence of any R. palatinus trigemini, and asserts 

 that the R. palatinus belongs to the Facialis. In Amphibia 

 the latter is true. It will not be possible to reconcile these 

 apparent discrepancies until special investigations have been 

 made upon more of the different types. It would seem quite 

 certain that in some cases, at least, a part of the R. palatinus 

 is derived from the lobus trigemini (Stannius, Wright), and 

 that the significance of this lies in the existence in the mouth 

 of numerous end buds to be innervated. It does not seem 

 possible, however, to relegate the supply of all these buds to 

 this source, inasmuch as we have some of them supplied by the 

 R. lingualis IX and even, possibly, by some of the Rr. 

 pharyngei and branchiales X in Amphibia. In this connection, 

 the view of Mayser that the lobus trigemini and lobus vagi are 

 similar structures comes again into consideration. While these 

 two structures obviously, from the final distribution of their 

 nerves, must be considered as largely different, yet the latter 

 may be conceived as containing a number of fibres to end buds 

 in the pharynx, while the lobus trigemini has been specialized 

 off to supply the great bulk of these structures in the mouth 

 and over the head and body. 



Respecting these preauditory roots, on a careful examination 

 of the most ventral root of the VII in Selachians I found this 

 root presented the appearance of a double root. Ewart seems 

 to have observed a similar appearance. As far as could be 

 judged from dissections merely, the R. palatinus consists of 

 fibres from both this double root and from the lobus trigemini 



