EVOLUTION 473 



mothers was for a certain character 2.221, for their 

 daughters 2.950, and for the array of daughters due to a 

 mother of given character 2.610 on the average. The 

 correlation between mother and daughter was .466, and 

 the regression of daughters on mothers .619. 



We have already seen that mothers are a selection, 

 and we should expect daughters to be somewhat more 

 variable than mothers (p. 442) ; something, however, of the 

 considerable difference here is probably due to change of 

 environment and growth ; but what is quite clear is this : — 



(i.) In asexual reproduction an individual does not 

 produce a facsimile of itself, and the variability of its 

 offspring is not immensely reduced below the variability 

 of the race.^ 



(ii.) The asexually reproductive individual has offspring 

 exhibiting regression, just like the sexually reproductive 

 individual. Its offspring tend to regress from the indi- 

 vidual to the race type. 



(iii.) With high probability, but not definitely, the 

 asexual individual represents the mid-parent, i.e. .4.66 

 and .619 are well within the probable errors of the values 

 .424 and .600, which we have found (p. 471) for the 

 correlation and regression of the mid-parent in the case 

 of bi-parental inheritance. 



We can now sum up our results for bi-parental in- 

 heritance : — 



{(t) Variability is not a product of bi-parental in- 

 heritance. 



The individual contains in itself, owing to a bathmic 

 law of growth, a variability which is quite sensible, being 

 80 to 90 per cent of the variability of the race. 



(d) The variability of the individual makes itself felt 

 not only in bi-parental reproduction but in autogamic and 

 parthenogenetic reproduction, and further in the un- 

 differentiated like parts of the same individual. 



1 The statement of Mr. A. Sedgwick, in his presidential address to Section 

 D of the British Association (Dover Meeting, 1S99), that these observations 

 exhibit a slight variability, is entirely erroneous. The average varialiiiity of 

 the offspring of a single mother is greater than the variability of all the 

 mothers ! 



