HARRIS: RELATIONSHIP OF OVULES TO SEEDS 251 
Applying Blakeman’s test* and using this time his more 
exact formula, 
iy VN boo) serene Sine ees 
2, org *¥ 5° VEE aw GH 
I find 
go — rr, =, = 000281, 
which gives 
¢/E; = 2.101. 
As far as one can state with certainity, therefore, the deviations 
of the observed means from the straight line due to the equation 
may be due to nothing more than the probable errors of random 
sampling. Comparing this diagram with those for other series 
of Cercis, I think it not unlikely that the falling off in the mean 
number of seeds for the pods with 8 ovules is biologically sig- 
nificant. 
Here again, the sign of the correlation, 7,:, is negative and its 
value very small. However 1,:/Er.: = 11.63, and perhaps it is a 
significant relationship. 
It may have occurred to the reader that the negative relation- 
ship between the number of ovules per pod and the capacity of 
the pods for maturing their seeds may be due to some purely 
mathematical difficulty in dealing with the biological data— 
perhaps to some approximation in the formula. 
To reassure:those who may be skeptical on this ground, I have 
actually determined the deviation of each number of seéds per 
pod from the probable number which would have occurred if 
fecundity had been the same throughout all the population and 
have determined the correlation between these deviations and 
the number of ovules per pod. 
In calculating the probable number of seeds for each pod the 
total seeds matured for all the pods was divided by the total 
Ovules formed to get P, the probability of any ovule in the entire 
Population—i. e., irrespective of the number of ovules in the pod 
in which it occurred—developing into a seed. This was 
P = 109,644/134,261 = .816,648. 
* Biometrika 4:°350,. 1005. 
