226 JoURNAL OF COMPARATIVE NEUROLOGY. 
From Table VII, in that paper is taken the following series 
of records comprising numbers 18-29, inclusive, (excluding 
numbers 21 and 24 for which the muscle weights were not 
determined). This is the series just as it stands in the original 
table, and these same records have also been employed in my 
paper ‘‘Ona Formula for Determining the Weight of the Cen- 
tral Nervous System of the Frog from the Weight and Length 
of its Entire Body,”’ 1902. 
For a description of the method by which the weights of 
the muscles were determined, the reader is referred to the 
original paper (p. 118). 
For the first five frogs entered in the table, calculation 
gives the following proportional values for the weights of the 
muscles of the thigh, shank and foot: 
TABLE III. 
Segment of Leg 
Percentage Value of Weight of Muscles. 
Thigh -63-9% 
Shank 24.3% 
Foot 11.8% 
In the case of the second five frogs in this same table, the 
proportional values are as follows: 
TABLE, LY: 
Segment of Leg, Percentage Value of Weight of Muscles. 
Thigh 63.9% 
Shank 245% 
Foot 11.6% 
It will be seen that these two series differ only by some 
tenths of a percent. in the case of the shank and foot, so that 
the relative values may be considered fairly constant. 
For use in the present investigation we take the average of 
the two series which gives: 
TABLE V. 
Segment of Leg. Percentage Value of Weight of Muscles. 
Thigh 63.9% 
Shank 24.4% 
Foot 11.7% 
Having obtained the data according to which the motor 
fibers entering the leg should be distributed, we need next to 
