44 REPORT OF THE CONFERENCE ON GENETICS. 
NOTES ON BIRDS OF Fo GENERATION, 
Blacks (no skin shown, as birds still being used in experiments).— 
Similar extracted blacks in F, from a cross between an F, barb fantail 
and F, barb nun have bred true. 
Blacks with few White Feathers (Skin III.).—A pair of these birds 
from mating (d) gave :— 
Black. Black with white feathers. Blue with white feathers. White. 
1 3 1 1 
The blue with white feathers is shown (Skin VII.). 
“ Blues” (Skin LY.).—The blue is seen chiefly in the tail, and the 
black tail-bar is well marked. These birds have been shown by experi- 
ment not to contain white. 
“ Blues” with few White Feathers (Skin V.).—These birds have been 
shown by experiment to contain white. Mating together the blues of the 
two types, gave blues with no white feathers, and blues showing several 
white feathers (Skin VIII.) in equal numbers. 
Reds.—Red was contained in one of the black barbs used. These 
birds are being dealt with in a separate experiment. 
Whites with few Coloured Feathers.—The coloured feathers may be 
black or red. Experiments are being made with them. 
Whites (Skin VI.).—A white in F, mated with a white fantail gave all 
offspring white. 
Skin IX. shows a blue containing white of the F', generation. 
To test whether a bird contains white it is mated to a white fantail, 
and is found to give all coloured offspring if it contains no white, or 
coloured and white offspring in equal numbers if white is being carried. 
Skins X., XI., and XII show the coloured offspring from the matings 
of the birds of the F,, F., and F3 generations respectively, with white 
fantails, 
Similar experiments are now in progress on the mating of the blue 
crossbreds with blacks. 
Exuipits By C. C. Hurst, BuRBAGE. 
Horsres.—Coloured drawings of bay, brown, and chestnut thorough- 
breds to illustrate Mendelian dominance of bay and brown over chestnut, 
segregation of chestnut from bay and brown, and the purity of the extracted 
chestnuts (for details see Proc. Roy. Soc. B. vol. Ixxvii. 1906, pp. 888-394), 
Rappirs.—Specimen coat-skins of “Belgian Hare” and “ White 
Angora” rabbits and their hybrid forms showing Mendelian dominance in 
I’, of short over Angora, coloured over white, grey over black ; segregation 
of these characters in F,, in Mendelian proportions; purity of recessives, 
purity and impurity of dominants in F;; also illustrating the fact that 
certain albinos may carry factors for coat colour and coat pattern, which 
characters only become visible when the albinos are mated with coloured 
animals (for details see Journ. Linn. Soc. [Zool.] vol. xxix. 1905, pp. 283- 
324). A photograph of the above exhibit is published with the Hybrid 
Conference paper. 
