Correlation and Fariatioti in the Toad 



587 



Millimeters 54.75 59.75 64.75 69.75 74.75 79.75 84.75 89.75 94.75 

 57.25 62.25 67.25 72.25 77.25 82.25 87.25 92.25 

 d^ = 2 4 3 16 23 48 41 21 12 I 2 

 9 = 1 5 2 4 II 14 22 27 32 46 38 24 13 7 4 2 



Fig. 6 Length of body. 



5 Correlation 



The degrees of correlation were determined for each character 

 with every other, again treating the sexes separately. In all 144 

 correlation tables were drawn and indices calculated.^ The 

 results are given in Tables V to XVII. The averages derived 

 from these tables are given in condensed form in Tables XVIII, 

 XIX. (The probable errors of the coefficients were determined 

 but are omitted from the tables.) 



2 r (coefficient of corre 



lation) = I — f 1' v^" I 



