314 0)1 the Nest and Efiffs of the Common Tern 
This relationship is hardly significant, and if significant only of very small in- 
tensity. It would indicate that the eggs of greater longitudinal girth were on 
the whole deposited in the more elaborated nests. 
To investigate the matter more closely we now correlated the length and 
breadth of the egg with the nature of the nest, obtaining Tables IV and V. 
Here the mean of the egg lengths in the simple nests is 4177 cms. and for the 
total population 4"206 cms. while the correlation is given by 
r = + 0953 + -0321. 
This is probably just significant although only slightly larger than that for 
the longitudinal girth. i 
TABLE V. 
Correlation of Nest Type and Breadtli of Egg. 
Breadth' of Egg. 
Type of 
Nest 
* 
1 
1 
to 
■?< 
1 
1 
1 
>^ 
CO 
,1 
1 
1 
1 
o 
^0 
i 
®o 
S-195 — 
1 
®i 
'0 
01 
Totals 
C 
Totals 
1 
3 
1 
1!) 
4 
32 
() 
54 
8 
1 20 
26 
1.54 
34 
200, 
34 
185 
21 
126 
6 
45 
3 
18 
3 
1 
143 
967 
1 
3 
19 
36 
60 
128 
180 
234 
219 
147 
51 
21 
3 
1 
1110 
2'695 — denotes all values from 2-595 to 2'G45, i.e. all the recorded values to two decimals from 
2-60 to 2-64. 
Here the mean of the egg breadths for the simple nests is 3"028, while for the 
total population it is 3'013. We have \ 
,• = -•0952 ± -0321, 
or the broader eggs are on the whole in the less-elaborated nests. Thus far then 
the rough nests appear associated with a short broad egg, although the correlations 
are only slight. 
With a view of analysing this point further we now investigate the correlation 
of the index with the type of nest. 
TABLE VI. 
Correlation of Nest Type and Egg Index B/L. 
Values of Index. 
Type 
of 
Nest 
1 
^1 
,1 
1 
1 
^1 
! 
CI 
^1 
1 
i 
1 
1 
•^ 
1 
I,-;, 
1 
J; 
00 
,1 
00 
01 -95— 
Totals 
S 
G 
2 
1 
17 
3 
33 
8 
71 
14 
168 
31 
229 
40 
213 
33 
142 
10 
59 
4 
23 
4 
3 
1 
1 
143 
967 
Totals 
2 
1 
36 
79 
182 
260 
253 
175 
69 
27 
4 
0 
3 
1 
0 
0 
1 
1110 
* 57'95 — denotes all values from 57*95 to 59-95, i.e. all recorded values from 58-0 to 59-9, the indices 
being recorded to one decimal place. 
