Variation in Hooks of Dog-Tapezvorms 



23 



headed X and the row headed Y give respectively the integral 

 parts of the deviations from the means of a and b. The Roman 

 numeral found in each quadrant indicates its number. The re- 

 maining tables are correlation tables for the characters a, b, c, 

 and d. 



After these introductory remarks we may at once enumerate 

 the results obtained as farther explanation of the methods used 

 seems unnecessary. 



COEFFICIENTS OF CORRELATION 



We gather from this table that, while the correlations of a to 

 b and a to c are mostly quite large, the correlations of b to c are 

 very small, and in two cases even negative. Or, in other words, 

 while a large a implies a large b and also a large c, a large b may 

 imply a small c. This apparent paradox is readily explained 

 when we consider that we are dealing with correlation "in the 

 long run," and that an infinite number of variations may arise 

 affecting characters b and c which belong to the same character 

 a, in such a way as totally to negate any expected correlation 

 between b and c. 



213 



