Donaldson, Nervous System of the Frog. 335 



XV. Length of Leg Bones. 



The length of the leg bones taken together, as compared 

 with the length of the entire frog is given in Table 1 1. 



TABLE II. 



Percentage of the entire length of frog 



represented by the sum of the lengths of 



the leg bones. 



Group I. 66. 8q^ 



Group II. 65.7^ 



Group III. 66.4% 



In Table 12, are given the percentage values of the length 

 of the three sets of bones, the sum of all three being consid- 

 ered equal to 100%. For the definition of "Foot" as here 

 used see section VIII, heading. Length. 



TABLE 12. 



Proportional lengths of 

 Femur Tibia Foot. 



Group I. 26.6 28.6 44.8 



Group II. 26.1 27.7 46.2 



Group III. 26.7 27.6 45.7 



From the foregoing, it is concluded that the weight of the 

 leg muscles as compared with that of the entire body is the 

 only relation that varies regularly with the size of the frog, and 

 even in that case, the variation is small. 



In other respects the weight and length relations of the 

 frog's leg are similar in frogs of all sizes. The general conclu- 

 sions from these observations are stated in the summary at the 

 beginning of the paper. 



Neurological Laboratory, 

 University of Chicago. 



