Table 4.
| I | Y | oo | Absent. | Total. | |
| Frequency | 235 | 291 | 144 | 12 | 682 |
| Percentage | 34.5 | 42.7 | 21.1 | 1.8 | ... |
The progeny of two extracted single-combed parents of the F2 generation give in 3 families the following totals: Of 95 F3 offspring, 94 have single combs; one was recorded from an unhatched chick as having a slightly split comb, but this was probably a single comb with a slight side-spur, a form that is associated with purely I-combed germ-cells. This result is in perfect accord with the second and third hypotheses, but is irreconcilable with the first hypothesis.
The progeny of two extracted oo-combed parents is given in table 5.
Table 5.
| [A] Median element recorded as "small" in these offspring. | ||||||
| [B] A median element visible in the mother, No. 2618. | ||||||
| Pen No. | Parents. | Comb in offspring. | ||||
| ♀ (F2). | ♂ (F2) | I | Y | oo | Absent. | |
| 729 | 2255 | 936 | ... | [A]4 | 36 | ... |
| 2269 | 936 | ... | ... | 29 | ... | |
| 756 | 369 | 1390 | 1 | ... | 3 | ... |
| 1067 | 1390 | ... | ... | 8 | 1 | |
| 1113 | 1390 | ... | ... | 13 | 4 | |
| 762 | 2011 | 444 | ... | ... | 10 | ... |
| 2011 | 2621 | ... | ... | 9 | ... | |
| 2333 | 444 | ... | [A]5 | 11 | ... | |
| 2333 | 2621 | ... | [A]1 | 2 | ... | |
| 2618 | 444 | ... | ... | 2 | ... | |
| 2618 | 2621 | ... | ... | 5 | ... | |
| 3776 | 444 | ... | ... | 2 | ... | |
| 3776 | 2621 | ... | 1 | 14 | ... | |
| 820 | 2016 | 4731 | ... | ... | 10 | ... |
| 2255 | 4731 | ... | ... | 16 | ... | |
| 5143 | 4731 | ... | ... | 45 | ... | |
| 6479 | 4731 | ... | ... | 31 | ... | |
| 832 | [B]2618 | 5119 | [B]1 | ... | 23 | ... |
| 3776 | 5119 | ... | ... | 28 | ... | |
| 4404 | 5119 | ... | ... | 9 | ... | |
| 4732 | 5119 | ... | ... | 3 | ... | |
| 5803 | 5119 | ... | ... | 21 | 2 | |
| 6481 | 5119 | ... | ... | 11 | ... | |
| 834 | 2324 | 5090 | ... | ... | 26 | ... |
| Total | 2 | 11 | 367 | 7 | ||
The distribution of offspring in the 24 families of table 5 is in fair accord with any of the three hypotheses, but seems to favor the second, for that hypothesis calls for families with combless children, whereas such are not to be expected on the first hypothesis. Moreover, agreement with the second hypothesis is fairly close, for that calls for 3 families with combless children and there were actually 3 such families showing a total of 1.8 per cent combless, where expectation is 2.8 per cent. What is opposed to any hypothesis is the appearance of some Y-combed offspring; and to account for this the hypothesis is suggested that the germ-cells of some parents with oo comb contain traces of the I-comb determiner. The word "traces" is used because the median element in these Y-combed offspring is practically always very small. It is fair, consequently, to conclude that oo × oo gives oo-combed, and occasionally combless, offspring. This conclusion is further supported by the statistics derived from extracted oo comb of all generations bred inter se, which give: Y 11, oo 427, and no comb 8, where the 11 Y-combed birds are those just referred to as progeny of F2 parents. The non-median comb, consequently, probably contains only non-median germ-cells.
Table 6.
| Pen No. | Parents. | Offspring. | |||||||
| ♀ (F2). | Form of comb | Degree of splitting. | ♂ (F2) | Form of comb | Degree of splitting. | I | Y | oo | |
| P. ct. | P. ct. | ||||||||
| 628 | 427 | Y | 5 | 439 | I | 0 | 5 | 1 | ... |
| 722 | Y | 20 | 439 | I | 0 | 1 | 5 | ... | |
| 725 | Y | 10 | 439 | I | 0 | 5 | 3 | ... | |
| 629 | 427 | I | 0 | 491 | Y | 50 | 9 | 6 | ... |
| 765 | 1790 | I | 0 | 1794 | Y | 90 | 17 | 25 | ... |
| 802 | 3846 | I | 0 | 6652 | Y | 90 | 8 | 5 | ... |
| 5025 | I | 0 | 6652 | Y | 90 | 14 | 11 | 2 | |
| 5087 | I | 0 | 6652 | Y | 90 | 13 | 17 | 2 | |
| 812 | 4254 | I | 0 | 4118 | Y | 90 | 15 | 13 | ... |
| 5540 | I | 0 | 4118 | Y | 90 | 8 | 9 | ... | |
| Totals (189) | 95 | 95 | 4 | ||||||
| Percentages | 49.0 | 49.0 | 2.0 | ||||||
The mating of extracted I comb and Y comb, both of the second (or later) hybrid generation, gives the following distribution of types in the offspring (table 6): Y comb 95 (49 per cent); I comb 95 (49 per cent); oo comb 4 (2 per cent). In detail the results given in table 6 accord badly with the second hypothesis, which demands some families with 100 per cent Y comb.