CoGHiLL, Cranial Nerves of Anibly stoma. 207 



Introduction. 



The nervous system of Amblystoma has already been the 

 subject of special microscopical studies by Stieda ('75) and 

 by Herrick ('94). It has also received notice in mono- 

 graphs of a more general nature by Osborn ('88), Strong 

 ('95), Kingsbury ('95) and others. Stieda made an 

 excellent contribution to the morphology of the central 

 nervous system, but gave little attention to the cranial nerves 

 themselves beyond the general relations of their roots and 

 ganglia. The studies of Osborn and Kingsbury con- 

 cerned chiefly the central system and the nerve roots ; while 

 Strong's observations upon Amblystoma, although they 

 were made from the point of view of both the central and the 

 peripheral relations of the neurones, were incidental to his 

 work upon the cranial nerves of the tadpole, and were, conse- 

 quently, of a fragmentary nature. Herrick's work, alone, 

 was offered as a systematic study of the cranial nerves of Am- 

 blystoma from the point of view of their central and peripheral 

 relations. This account, l^owever, is incomplete with reference 

 to several important nerves and does not, Professor Herrick 

 authorizes me to say, represent his "present views in some 

 matters of anatomical detail and many of morphological inter- 

 pretation." 



In the absence, therefore, of an accurate and comprehen- 

 sive account of the cranial nerves of Amblystoma according 

 to the later neurological methods, I have undertaken to ascer- 

 tain the composition and distribution of all the cranial nerves, 

 including the first two spinal nerves, and to estimate their true 

 morphological value. The results of this investigation are 

 presented in this paper under two main heads: Part First, 

 which is purely descriptive ; Part Second, which is a discussion 

 of Part P'irst in the light of recent research upon the cranial 

 nerves of vertebrates. 



My purpose in Part First is to give such a description as 

 will be of value to those who are interested in the comparative 

 study of the cranial nerves. This purpose demands a consid- 



