236 JOURNAL OF COMPARATIVE NEUROLOGY. 
Thus all the fibers entering the leg were in the sections at 
the levels C+S,. All the fibers entering the shank were in the 
sections at P+T, and all the fibers entering the foot at P1+P2 
and T1+T2. 
In the Tables XII-XVI which follow, these designations 
are used to indicate the levels at which all the fibers for a given 
segment were to be found. Below the entry for the number of 
fibers to each of the segments, stands ‘‘To Thigh” and ‘‘To 
Shank,’ which means that all the branches to the thigh or to 
the shank contained the numbers there entered, under 
‘‘observed.”’ The number of fibers immediately below the 
branches to the thigh is also given after Su». 
In the column headed ‘‘ muscular and cutaneous,”’ are the 
observed numbers found in the muscular and cutaneous 
branches and their sum is equal to the ‘‘ observed number ’”’ in 
each case. 
In the column headed ‘‘calculated,’’ we have the number 
determined by Dr. Dunn by taking the difference between the 
number just above the branches to the thigh (C+S, ), or shank 
(P+T), and the number just below at S: or at Pi+P2 and 
ash: 
In the column marked ‘‘splitting fibers,” we have the 
’ 
difference between the observed—the larger number—and the 
calculated—the smaller number—which difference is due to 
fibers that have split in their course so that they are repre- 
sented either by two divisions having the same distribution 
(i. e., both run in the branches supplying the segment), or by 
one division running in the branches to the segment, and by 
the other in the main trunk of the nerve to some point below 
the Jevel of the branches. It is the presence of these splitting 
fibers which renders complicated the application of the test 
which it is proposed to make, since the formula based on the 
law of distribution does not take account of the additional fibers 
which appear as the result of splitting. 
