feathers in the breed of fowls called Plymouth Rock. In this the female is
heterozygous for sex as in _Abraxas grossulariata_, and the barred
character is sex-linked. When a barred hen is crossed with an unbarred
cock all the male offspring are barred, all the females plain. On the
other hand, if a barred cock is crossed with an unbarred hen, the barred
character appears in all the offspring, both and females. The female thus
transmits the character only to her sons. If we represent the barred
character by _B_, and its absence by _b_, we can represent the heredity as
follows:--

BARRED FEMALE WITH UNBARRED MALE

B female b male X b male b male

Bb male bb female

Barred male. Unbarred female.
Heterozygous. Homozygous.


B male B male X b female b male

B male b female b male b male

Barred female. Barred male.
Heterozygous. Heterozygous.]

This case is thus exactly similar to that of _Abraxas grossulariata_ and
_A. lacticolor_. The barred character like _grossulariata_ is dominant,
the unbarred recessive, and to explain the results it is necessary to