+------+---+----------------------------+-------------------+-----+--------------------------------------+ | | | Mother. | Father. | | Grade of openness in offspring. | |Serial|Pen+---+-----+--------------+---+----+----+-----+---+Total+----+----+----+---+---+--+---+--+--+--+ | No. |No.| | | | | | | | | gr. | | | | | | | | | | | | | |No.| Gen.| Races. |Gr.| No.|Gen.|Race.|Gr.| | 1 | 2 | 3 | 4 | 5 | 6| 7| 8| 9|10| +------+---+---+-----+--------------+---+----+----+-----+---+-----+----+----+----+---+---+--+---+--+--+--+ | 13 |768|298| F2 |Med. × Polish.| 2 |1689| P. |Med | 1 | 3 | 11 | 9 | 3 | 1 | 3 |..| 1|..|..|..| | 14 |768|509| F1 | Do. | 1 |1689| P. | Do. | 1 | 2 | 12 | 5 | 6 | 1 | 1 | .| ..|..|..|..| | | | | | +----+----+----+---+---+--+---+--+--+--+ | | | | | Totals (53) | 23 | 14 | 9 | 2 | 4 | 0| 1 |..|..|..| | | | | | Percentages |43.4|26.4|17.0|3.8|7.6|..|1.9|..|..|..| +------+---+---+-----+--------------------------------------------+----+----+----+---+---+--+---+--+--+--+ The study of the tables 45 to 54 establishes the following conclusions: First, high nostril is dominant. This means that there is a factor that inhibits the development of the narial flap. In the absence of such a factor the flap goes on developing normally. This hypothesis is opposed to the conclusion that I reached in my report of 1906 (pp. 68, 69). I there said: A close agreement exists between the percentage obtained in each generation and the expectation of the Mendelian theory, assuming that narrow nostril is dominant. The statistics do not, however, tell the whole story. In 36 per cent of the cases in the F1 generation the nostril was wider than in the "narrow" ancestor. Even in the F2 generation nearly half of the "narrow and intermediate" were of the intermediate sort. This intermediate form is evidence that dominance is imperfect and segregation is incomplete. TABLE 48.--_Distribution of frequency of grades of "openness" in offspring when both parents are heterozygous (DR × DR)._