| | | | | +=====+=====+=====+====+========+====+====+=====+====+====+=====+====+ | 7 |820| 984|F2 |Wh. Legh. × Houd.|4731|F3 |Wh. Legh. × Houd.| D × DR| 2 | 3 | 27 | .. | 9.78 | 2 | 2 | .. | 1 | 27 | .. | .. | | 8 |820|2255|F2 | Do. |4731|F3 | Do. | DR × DR| 6 | 1 | 10 | .. | 9.24 | 6 | .. | .. | 1 | 10 | .. | .. | | 9 |820|6479|F3 | Do. |4731|F3 | Do. | DR × DR| 12 | 2 | 16 | .. | 9.13 | 10 | 1 | 2 | 1 | 15 | 1 | .. | | 10 |820|2016|F1[A]| Do. |4731|F3 | Do. | DR × DR| 9 | 2 | 2 | .. | 8.45 | 9 | 2 | .. | ..| 2 | .. | .. | | | | | | +-----+-----+-----+----+--------+----+----+-----+----+----+-----+----+ | | | | | Totals (92) | 29 | 8 | 55 | .. | 9.28 | 27 | 5 | 2 | 3 | 54 | 1 | .. | | | | | | Percentages | 31.5| 8.7 | 59.8| .. | .. |29.3| 5.4| 2.2| 3.3|58.7| 1.1 | .. | +------+---+----+-----+-------------------------------------------------------+-----+-----+-----+----+--------+----+----+-----+----+----+-----+----+ [A] No. 2016 has 4-4 toes and is a hybrid between a 5-toed White Leghorn × Houdan and a 4-toed Minorca × Polish. But a more critical examination of the parentages of the 5 pens shows that they are not comparable. In matings 6 to 14 of table 20 the cock is almost certainly a dominant in respect to toes; whereas the cocks in table 21 are probably heterozygous. The heterozygous state determines two things: the imperfect nature of the extra-toe and a relative deficiency in the offspring of the higher toe-numbers. In our results we can not say that one of these things is the cause of the other, as Castle does; they are, rather, in all probability, due to a common cause. I think Castle's paper may justly be criticized for not giving sufficient data concerning the ancestry of the individual mothers used. Without such data the paper can not be said satisfactorily to demonstrate his conclusion. TABLE 22.--_Summary of observed toe-numbers in offspring, percentages._