Dunn, Netve Fibers of the Frog. 315. 



plained by the fact that the point of section for these fibers was 

 much nearer to the periphery than that for the fibers to the 

 thigh. As has been indicated eariier in this study, the branches 

 to the shank are given off to single muscles or frequently several 

 branches pass to one muscle, while in the thigh the larger 

 branches furnish fibers to several muscles, in one instance, the 

 ramus profundus posterior, to eight muscles. 

 3. Discussion of the increase in the number of fibers at succes- 

 sive levels. 



Enumerations of the fibers at two levels other than those 

 already mentioned were made that they might serve as controls 

 to the results obtained at the levels just below the branches to 

 the thigh and just above the branches to the shank. At no 

 point between these four levels are nerve branches given off 

 with the exception of a few very fine branches of four or five 

 fibers each, which cannot be traced by fine dissection but 

 seem to pass to surrounding tissues other than muscular tissue. 

 From the level in the sciatic nerve just below the thigh 

 branches, indicated in Figure 2 by S^ , through the levels indi- 

 cated in the same figure by S3 and T-f P, to the level just above 

 the branches to the shank, level T and P, the number of fibers 

 shows a gradual increase. Reference to Table XII reveals the 

 exact amount of this increase from one level to the next one» 

 This increase must be due to fibers dividing in the main trunk. 



TABLE XII. 

 Showing gradual increase in the number of fibers at successive 

 levels between the separation of the last branch to the thigh and that 

 of the first branch to the shank. 



Frog II B. 

 Levels 



S2 



S3 



T-fP 

 Tand P 



