554 Journal of Comparative Neurology and Psychology. 



geal rami in the branchial nerves; possibly also the ramus lateralis 

 VII; the lateral line lobe; all these have distinctly fish-like charac- 

 teristics. Although the nerves connected with the eyes are degen- 

 erate, this cannot be said of the other cranial nerves. As com- 

 pared with other Urodela, Amphiuma shows in the arrangement 

 of its cranial nerves a tendency towards great diffuseness and 

 individual variabihty. A nerve trunk in one individual may 

 break up into a number of divisions later to become consolidated 

 into a main trunk again. In another specimen the same nerve 

 may show no such tendency to diffuse subdivsion. General con- 

 clusions based upon one or two specimens, in Amphiuma at least, 

 are likely to be much in error. 



The resemblances between the cranial nerves of Amphiuma 

 and those of Amblystoma are very striking. When the com- 

 ponents of the cranial nerves of Cryptobranchus, Necturus, Siren, 

 and one or two more of the Salamandridse have been carefully, 

 worked out, we shall be in a position to define the urodele type of 

 cranial nerves, and in the opinion of the writer, not until then. 



The distribution of the lateral line organs of Amphiuma has 

 been carefully mapped out and described by Kingsbury (1895b). 

 The innervation of these organs on the head has been worked out 

 by the writer with precision, corroborating the description of 

 Kingsbury, except in some details. A detailed account of the 

 innervation of these organs in Amphiuma is withheld from this 

 paper because of the uncertainty as to the exact distribution of 

 the ramus lateralis VII on the trunk of the body. 



Iowa College, 

 June 20, 1908. 



LITERATURE CITED. 



Bowers, Mary A. 



1900. The peripheral distribution of the cranial nerves of Spelerpes bilineatus. Proc. Amer. 



Acad. Arts and Sci., vol. 36. 

 Clapp, Cornelia M. 



1898. The lateral line system of Batrachus tau. Jour. Morph., vol. 15. 



COGHILL, G. E. 



1902. The cranial nerves of Amblystoma tigrinum. Jour. Comp. Neurol., vol. 12. 



1906. The cranial nerves of Triton tseniatus. Jour. Comp. Neurol, and Psych., vol. 16. 

 Druner, L. 



1901. Studien zurAnatomiederZungenbein-,Kiemenbogen-,und Kehlkopfmuskeln der Urodelen. 



I Theil. ZooL Jahrh., Bd. 15. 

 1904. Studien zur Anatomie der Zungenbein-, Kiemenbogen-, und Kehlkopfmuskeln der. 



Urodelen. II Theil. ZooL Jahrh., Bd. 19. 

 Fischer, J. G. 



1864. Anatomische Abhandlungen iiber die Perennibranchiaten und Derotremen. Hamburg 



