348 
J. A DETLEFSEN AND E. ROBERTS 
Series C; high selectio7i -* 
In the Fi generation of series A, pair number 21, was chosen 
to begin a high-selection series, series C. While this series was 
carried for only eight generations, and then discarded in order 
to devote time to the other series, nevertheless brief mention 
should be made because the results may aid us in interpreting 
series A, A', and B. We were not able to make progress in 
selecting upward, as the averages of table 5 show. (Table 5 
was constructed in the same way as tables 1, 2, and 3.) On 
the contrary, we were much surprised to find that in the F7 
generation a number of pairs suddenly dropped to very low 
TABLE 5 
Series C: high selection 
GENERATION 
NUMBER OF PAIRS 
CROSSOVERS 
TOTALS 
CROSSOVER VALUES 
F, 
28 
427 
1,575 
27.11 
r2 
162 
512 
31.64 
F3 
35 
1,407 
4,842 
29.06 
F4 
436 • 
1,355 
32.18 
Fa 
90 
6,465 
21 ,071 
30.68 
Fe 
684 
2,267 
30.17 
F7 
72 
3 ,893 
13 ,705 
28.41 
Fg 
296 
1,298 
22.80 
crossover values; in fact, much lower ratios than one would 
find in any ordinary population such as our original stocks or our 
Fi of table 1. The distribution of the F7 in series C is given in 
table 6. It will be noted that nine pairs gave values lower than 
6 per cent. Their values were as follows: 
4:72 
= 5.56 
5:279 
= 1.79 
9:164 
= 5.49 
1:142 
= 0.70 
1:82 
= 1.22 
0:123 
= 0.00 
4:104 
= 3.85 
2:40 
= 5.00 
0:49 
= 0.00 
Total, 26:1055 = 2.46 
