372 The Egg of Cucidus Canorus 
B. With 1 mm. unit of grouping. 
Length 
18- 75— 19-75 
19- 75—20-75 
20- 75-21-75 
21- 75—22-75 
22- 75—23-75 
23- 75—24-75 
24- 75-25-75 
25- 75—26-75 
Totals 
prejudice in favour of the half and whole millimetres may have tended to obscure 
some of the points involved and renders it difficult to deal satisfactorily with the 
distribution of frequency. The multimodal character of the previous distributions 
(see Biometrika, Vol. I. pp. 175 and 176) was chiefly due to the manner in which 
this emphasis of certain values upset the grouping. Admitting the defect the only 
legitimate gi'ouping is that which takes an entire millimetre as its unit, but this is 
very coarse, especially in the case of the breadths, for the purpose of drawing any 
conclusions. In Table V. B the frequencies are given with 1 mm. unit of grouping 
and we see that the '5 mm. modes have disappeared, but the grouping is very 
coarse. Working, however, from these we find : 
TABLE VI. 
Authority 
Rey ... 
0. H. L. 
Total 
An examination of this table seems to indicate that the English Cuckoo's egg 
is for both dimensions slightly larger and more variable than the German. The 
difference, however, is not such that we can lay any stress upon it, and in round 
numbers we may certainly take : 
Length of egg 22'4, Breadth 16 6, standard deviation of Length = '96 and of 
Breadth = 60. 
The following results were obtained by calculating the normal curves for four 
sets of frequencies* : 
* The determination of P, the goodness of fit, from x" lias been made by aid of Palin Elderton's 
Tables, Biometrika, Vol. i. p. 159. 
Number 
Number 
Breadth 
Eey + 0. H.L. 
Key 
ouly 
O.H. L. 
only 
Eey + 0. H.L. 
Bey 
only 
0. H.L. 
only 
4 
72 
308 
680 
386 
107 
14 
1 
50 
185 
380 
185 
46 
8 
3 
22 
123 
300 
201 
61 
6 
13- 75—14-75 
14- 75-15-75 
15- 75—16-75 
16- 75-17-75 
17- 75—18-76 
18- 75—19-75 
3 
121 
838 
571 
37 
2 
1 
74 
459 
302 
19 
0 
2 
47 
379 
269 
18 
2 
1 
0 
1 
Totals 
1572 
855 
717 
1572 
855 
717 
Mean in mm. 
Length 
Breadth 
Length 
Breadth 
22-266 
16-559 
-9450 
•5955 
22-486 
16-613 
-9546 
•6021 
22-366 
16-.583 
•9557 
•5992 
Standard Deviation 
in mm. 
