CoGHiLL, Cranial Nerves of Amblystoma. 209 



munis; the term "lateralis," as applying to the neurones 

 which innervate the organs of the lateral line system. 



In presenting these results for publication in the Journal of 

 Comparative Neurology, I would express my deep obligation to 

 the Editor, Dr. C. L. Herrick, under whose inspiring 

 instruction I began the research in the University of New 

 Mexico ; and to Professor C. Judson Herrick for his 

 kindly interest and helpfulness in many matters of impor- 

 tance. I would thank, also. Dr. H. C. Bumpus and Pro- 

 fessor A. D. Mead, through whose kindness I have had for 

 two years the liberal advantages of the Anatomical Laboratory 

 of Brown University. I am further indebted to Brown Uni- 

 versity for the Grand Army of the Republic Fellowship during 

 the past year. 



PART FIRST. 



A DESCRIPTION OF THE CRANIAL AND FIRST TWO SPINAL 

 nerves OF AMBLYSTOMA TIGRINUM. 



I. The Olfactory Nerve. 



The glomeruli olfactorii in Amblystoma appear on the 

 lateral side of the anterior half of the cerebral hemisphere. 

 At the surface of the glomeruli two elements of the olfactory 

 nerve are distinguishable. A posterior and smaller element 

 occupies in its origin the most caudal and ventral region of the 

 area of exit of the entire nerve, and it is separated from the 

 anterior and larger element in the proximal portion by a double 

 septum of the pia. The fibers of the posterior element 

 become connected into a distinct bundle before they come in 

 contact with the anterior element. These two elements soon 

 unite to form the olfactory nerve and become macroscopically 

 indistinguishable. Their respective courses can be followed 

 farther only in exceptional cases by means of serial sections. 



The anterior element takes first a lateral position in the 

 olfactory trunk, but becomes twisted ventrad relative to the rest 

 of the nerve by the anterior element which arises at a slightly 

 more dorsal level ; so that, as the olfactory nerve breaks up 



