GENETICS: CASTLE AND HADLEY 
41 
undoubtedly heterozygous, varied in whiteness from grade 1 to grade 
4, figures 1 to 4, the modal or commonest condition being about the 
same as that of the father (grade 2). The distribution of the young 
in relation to our grades is shown in the Table. Statistical treatment 
of the table gives the average grade of the young as 2.43, that is some- 
Table Showing the Distribution of Grades of Offspring in the First and 
Second Series of Matings for Each Individual Mother 
MOTHER 
SERIES 
GRADES OF YOUNG 
TOTALS 
AVER- 
AGE 
1.00 
1.25 
1.50 
1.75 
2.00 
2.25 
2.50 
2.75 
3.00 
3.25 
3.50 
3.75 
4.00 
Ser.I 
Ser. II 
16A < 
1 
3 
2 
1 
2 
1 
2 
1 
7 
3 
3 
5 
21 
2.30 
o . yjo^ 
16B < 
1 
1 
3 
1 
1 
1 
2 
1 
11 
1 
1 
2 
1 
1 
2 
1 
3 
12 
2.67 
16D 1 
I 
2 
5 
1 
2 
3 
1 
14 
2.79 
3 
1 
6 
2 
12 
3.19 
16E 1 
2 
5 
2 
1 
1 
1 
3 
1 
1 
12 
5 
3.50 
16F I 
1 
2 
1 
5 
3 
2 
3 
17 
9 69 
. uz 
1 
is 
1 
o 
O 
o 
1 
11 
2.48 
16G 1 
I 
1 
2 
2 
3 
1 
2 
3 
1 
15 
2.35 
1 
2 
2 
3 
1 
2 
1 
1 
13 
3 06 
16H 1 
1 
3 
3 
1 
2 
2 
2 
1 
2 
1 
18 
2.76 
3 
2 
1 
1 
8 
2 
2 
1 
20 
3.06 
17E 1 
1 
1 
3 
4 
3 
3 
1 
1 
2 
2 
21 
2.36 
1 
2 
5 
5 
3 
4 
4 
2 
1 
27 
2.97 
17G I 
1 
9 
6 
3 
3 
2 
1 
2 
1 
1 
29 
2.27 
1 
1 
1 
1 
1 
1 
1 
1 
1 
9 
2.44 
18D 1 
1 
3 
3 
3 
1 
2 
2 
15 
2.53 
2 
1 
2 
3 
1 
2 
6 
16 
2.91 
18F 1 
3 
1 
1 
1 
2 
4 
2 
1 
1 
1 
2 
2 
5 
16 
2.15 
2.97 
18H 1 
1 
1 
3 
1 
1 
3 
10 
2.43 
1 
3 
3 
4 
2 
3 
1 
2 
19 
2.87 
2A 1 
1 
2 
1 
1 
4 
2 
3 
1 
15 
2.22 
1 
2 
1 
2 
2 
8 
2.78 
Totals 1 
1 
5 
10 
18 
33 
31 
24 
16 
18 
11 
13 
6 
1 
187 
2.43 
1 
2 
5 
17 
13 
19 
29 
18 
37 
27 
14 
7 
189 
2.92 
what darker than the father. Inspection of the table shows that more 
than half of the young are darker than the father, which supports in 
a general way the statistical average grade. If we consider separately 
the average grade of the young produced by each mother, we find that 
it ranges from 2.15 in the case of 9I8F, which had 5 English young, 
to 2.79 in the case of 9 16D which had 14 English young. The average 
number of young to a mother is 14.4. 
