[1] Excluding 6 doubtful because from too young embryos and not observed by myself.

[2] One is reported as having a I comb; probably the limiting condition, again.

[3] E. g., Pen 813, 935 ?, embryo from egg of May 13.

[4] I say probably of the duplex type because the cock of pen 769 had a distally split toe on the right foot, reminding somewhat of the reduced triplex type. But as the left foot had a typical duplex thumb, and the triplex is not common in Houdans, it should probably be classed as duplex.

[5] Lewis and Embleton (1908, p. 45) present strong arguments against the theory that syndactylism is due to arrested development.

[6] Davenport, 1906, page 34, Plate V.

[7] Davenport, 1906, pages 62 to 64, fig. 46.

[8] Thus Wright (1902) says the shanks of the Silkies (in England) are "slightly feathered," and Baldanus (1896) says that (in Germany) they are feathered on the outer half.

[9] Bateson and Punnett (1908, p. 28) recognize three "kinds" of recessive whites—that of the Silkie, that of the Rose-comb bantams, and that of "white birds that have arisen in the course of our experiments." White Cochins have perhaps been one of the ancestors of Rose-comb bantams; Bateson's new white lay recessive in the White Dorking and when mated to the White Silkie throws Game-colored offspring.

[10] Wright (1902, p. 401) recognizes the variability of the blues. He advises the breeder of Andalusians that: "Black and white ones [offspring] can be weeded out at once; two or three months later birds absolutely too light, or dark and smoky, can be selected."

[11] 1906, page 49, figs. 35, 37, 37a.

[12] Goodale, 1909, has shown that in Plymouth Rocks males may be and females usually are heterozygous in barring. There is thus a clear difference between the barring of the Cochin × Tosa hybrid and that of the Plymouth Rock. The question of the heterozygous nature of the female sex, fully discussed by Goodale, will be considered by me in another place. [Note at time of correcting proof.]

[13] Does the graying of human hair represent an ontogenetically advanced condition of the melanic pigment as yellow represents the embryonic condition?

[14] Davenport, 1908, page 60.

[15] By homologous matings I mean those in which the germ-plasms of both parents are in the same condition with reference to the unit-character; i. e., both either possess it pure or lack it altogether.

[16] Davenport, 1906, page 86.

[17] Mendel's expression on this subject is translated by Bateson (1902, p. 84) as follows: "Whoever studies the coloration which results in ornamental plants from similar fertilization can hardly escape the conviction that here also the development follows a definite law which possibly finds its expression in the combination of several independent color characters. (The italics are Mendel's.)

[18] "An inherent tendency to reversion is evolved through some disturbance in the organization caused by the act of crossing." (Darwin, Animals and Plants under Domestication, Chapter XIII, section, "Summary on proximate causes leading to reversion.")

[19] Plate 11.

[20] Davenport, 1906, page 35.