190 "Journal of Comparative Neurology and Psychology. 



the internodal lengths are greater in the sciatic than in the spinal 

 roots. These values are given in Table 14. 



TABLE 14 



Showing in Frog 8 the lengths of the internodes on fibers lo/i, 11.25// and 12.5/i in 

 diameter from the ventral and dorsal roots of the IX nerve, and from the sciatic 

 at the level S^. The numbers in parentheses indicate the number of measure- 

 ments made in each case, and apply to the internodal value above which they 

 are placed. 



Just what interpretation is to be given to the difference in the 

 internodal lengths, from these several localities, must await the 

 collection of a much larger number of observations. 



We turn next to the comparison of the length of the internodes in 

 the III, with those in the IX spinal nerve. Owing to the tech- 

 nical difficulties already mentioned, p. 171, we have only a limited 

 number of observations on the ventral root of the III nerve of Frog 

 2, to be compared with those on the fibers in the ventral root of the 

 IX nerve from the same frog. If we select the fibers lO/i to i5/< 

 in diameter, inclusive, and tabulate the average values of the inter- 

 nodes for each diameter class, we get the results presented in Table 



15- 



TABLE 15. 



Giving the length of the internodes on fibers lo/jt to i^p. in diameter, in the ven- 

 tralroots of both the III nerve and IX nerve of Frog 2. The numbers in 

 parentheses indicate the number of observations. 



