284 Journal of Comparative Neurology. 



12. There is no constant arrangement in Amblystoma of 

 the roots of the vagus into a particular number of rootlets 

 which can be compared with the arrangements described by some 

 authors in other Urodela. In composition the roots of the 

 vagus are constant throughout the Amphibia, in so far as they 

 have been adequately studied. 



13. The r. supratemporalis of Amblystoma corresponds 

 to the nerve of the same name in the tadpole of the frog. The 

 nerve has been misinterpreted by Bowers in Spelerpes and by 

 Druner in Menobranchus. 



14. The rr. laterales superior and inferior are constant in 

 their relations in all the Urodela. The r. lateralis inferior has 

 been wrongly figured as a motor nerve by Bowers. 



15. The r. communicans IX+X ad VII, in so far as it is 

 general cutaneous, corresponds to the nerve of the same name 

 in Anura. It differs from the latter nerve, howex^er, in having 

 a communis component. The composition of the nerve in 

 Amblystoma speaks strongly against Druner's interpretation of 

 the r. communicans in other Urodela. 



16. Jacobson's anastomosis does not appear in Anura and 

 is wanting also in some Urodela. The relation of this anasto- 

 mosis to the Jacobson's anastomosis of fishes is doubtful. 



ly. The nerves to the external gills should not be 

 classed with the pre-trematic and post-trematic nerves. 



18. The pre trematic nerves of Amblystoma are typical 

 for Urodela, and indicate a closer affinity between the inner- 

 vation of the gill clefts in Amphibia and that in fishes than has 

 been otherwise demonstrated. 



19. There is no plexus subceratobranchiales in Ambly- 

 stoma like that described by Druner for other Urodela. The 

 N. cutaneus retrocurrens IX of Driner in Salamandra in- 

 creases the probability which appears in Amblystoma that 

 there are terminal buds in the skin of some larval Urodela. 



20. The hypoglossal nerve is formed in all Urodela by 

 the fusion of the ventral motor branches of the first and sec- 

 ond spinal nerves, and in some species by the addition of 

 spino-occipital nerves. The roots of all these nerves arise 



