458 
Tntra-Class and Liter-Class Correlations 
These give : 
_ { S[Z(o')]*-S[Z(o'>)l}[S[n(n- 1)] - _ 
\S [2 (0? - S [2 [n (n - 1)] - ? 
= -449. 
The number of individuals is too small to attach much importance to the 
result but the agreement with other series of Leguminosae is good*, although the 
correlation for seeds maturing is frequently considerably smaller than that for 
ovules formed. 
TABLE VIII. 
Summations for Individuals of Robinia. 
Number 
of 
Tree 
n 
n(h-l)- 
Sum of 
Ovules, 
2(o') 
Sum of Ovules 
Squared, 
2 (o'*) 
Sum of 
Seed, 
S(s') 
Sum of Seeds 
Squared, 
2 
1 
122 
14762 
1273 
13649 
912 
7394 
o 
64 
4032 
796 
10256 
602 
6522 
S 
111 
12210 
1183 
12839 
595 
3543 
4 
102 
10302 
1064 
11310 
586 
3938 
5 
122 
14762 
1378 
15896 
864 
6918 
a 
120 
14280 
1299 
14311 
555 
3091 
7 
120 
14280 
1490 
18850 
713 
4819 
8 
159 
25122 
2251 
32331 
1495 
15117 
9 
128 
16256 
1580 
19816 
860 
6894 
10 
78 
6006 
946 
11690 
457 
3211 
11 
105 
10920 
1245 
15135 
984 
9642 
12 
196 
38220 
2875 
42989 
2347 
30661 
Totals 
1427 
181152 
17380 
219072 
10970 
101750 
Illustration (III—Ab) 0. Tests of the Existence of Sub-races. 
O. H. Latter in testing for differentiation in Cuckoo's eggsj - according to their 
foster parents, determined the probable errors of the difference between the means 
of the several " gentes " and the means of Cuculus Canorus as a species. But one 
may also test for the differentiation of the foster parent "gentes" from the species 
as a whole by determining the intra-class correlation for egg dimensions. I am 
especially willing to do this since Latter tested the significance of his divergences 
by the formula - 67449 sj ^ 
(- , whereas Pearson's formula 
•67449 
N + n 
1 - 
2n\ n (M - m)- 
N) N(N-n) 
would have been more suitable but had not then been publishedj. 
* Pearson, Phil. Trans. A, Vol. cxcvu. pp. 364—379 ; Harris, American Naturalist, Vol. xlv. p. 570. 
t Biometrika, Vol. i. pp. 164—176, 1901 ; Vol. iv. pp. 363- 373, 1905. 
t Ibid., Vol. v. pp. 181—183, 1906. 
