APPLICABILITY OF A COEFFICIENT OF CORRELATION 333 



(a) distance from the anterior end of the organism to the posterior mar 

 gin of the mouth, (fe) distance from the posterior margin of the mouth 

 to the posterior end of the organism, and (c) the total length in series of 

 conjugant and non-conjugant Paramecia. 



He has calculated and discussed for a purpose which does not con 

 cern us here the correlations between certain of these dimensions. All 

 the correlations between the absolute measurements, calculated from his 

 data, are given in table 2. 



TABLE 2 



Relationship between total length, I, and anterior length, a, and between anterior length 

 and posterior length, p, in Paramecium. 



* Lot /, table 40, conjugates of wild cultures. 2. Lot 7, table 41, non-conjugants 

 of wild cultures. 3. Lot 19, table 51, conjugants of race g. 4. Lot 19, table 52, 

 non-conjugants of race g. 5. Lot 22, table 55, wild culture conjugants not yet sep 

 arated. 6. Lot 22, table 56, wild culture conjugants about twelve hours after separa 

 tion. 7. Lot 24, table 64, unseparated conjugants of race k. 8. Lot 24, table 65, con 

 jugants of race k about twelve hours after separation. 



In this table the constants for anterior and posterior length are ar 

 ranged in pairs of conjugants and non-conjugants or ex-conjugants. In 

 every instance the correlation between the anterior and posterior por 

 tions of conjugants is lower than that between the same dimensions in 

 non-conjugants or ex-conjugants. 2 



All of these values are low, as JENNINGS has noted. In the case of 

 lot 22 the coefficient for the conjugants is actually negative in sign. 



The correlation between total length and the length of the section 

 anterior to the mouth is high. In every case the value of r ia is higher 

 in non-conjugants or ex-conjugants than in conjugants. The additional 

 relationship to be brought out by the formulae here under discussion is 



2 See in this connection the discussion by JENNINGS (1911, pp. 65-66, 71-73)- 



GENETICS 3: Jl 1918 



