270 Pearl and Surface. 
producing ability. This seeming paradox might arise in this way- 
If unfavorable environmental influences acted in the case of daughters 
the average production of the whole group of daughters might be 
considerably below that of the mothers. At the same time the 
exceptional mother (that is the mother whose production was above 
the average for mothers) might produce the exceptional daughter 
(the daughter whose performance was above the average for daughters). 
Such a condition of affairs would obviously indicate the inheritance 
of egg producing ability and yet clearly might exist quite independently 
of the relative magnitude of the averages of the mother and daughter 
groups as wholes. 
To determine whether there is such an inheritance of egg producing 
ability independent of the group averages it is necessary that the 
correlation between mothers and daughters in respect to egg 
production be actually measured. From such measurement it can be 
told whether on the average the exceptional mother produces the 
exceptional daughter or whether the exceptional daughter is as likely 
as not to be the daughter of the mediocre or poor mother. 
Such correlations have been determined for each laying period. 
The net result is to show that in this material tliere is no sensible 
correlation between mother and daughter in respect to egg 
production. In other words there is no evidence that fluctuating 
variations in this character were inherited in the mass in this 
experiment. This lack of correlation is shown graphically in Fig. 4 
which compares mothers and daughters in respect to winter egg 
production. If there were an inheritance of fecundity it would be 
expected that the two zigzag lines in this figure would take a more 
or less parallel course. This they obviously do not do. 
Turning to the question as to whether the daughters of ‘‘200-egg”’ 
hens were or were not better egg producers than other birds not of 
such highly selected ancestry (see p. 262 supra) when kept under 
identical environmental conditions we have the comparative figures 
given in Table ITI. 
From the table it appears that: 
I. With a single exception where the difference is very small 
(100 bird pens) the mean production of the ‘unregistered’ (less 
closely selected) birds was in all cases higher than that of the 
“registered” (more closely selected) birds. In other words the data 
show that the daughters of ‘‘200-egg”’ hens are certainly not 
