118 REPORT OF THE CONFERENCE ON GENETICS, 
Grey Coat Cotour IN THE ‘ BELGIAN Hare’ RABBIT. 
In my experiments the pure-bred ‘Belgian Hare’ with a grey coat 
was crossed with the pure-bred ‘ White Angora’ with a white coat. In 
I’, all the offspring had grey coats (see fig. 27). In F, there were approxi- 
mately nine grey: three black: four white (127 : 44 : 53) (see fig. 28). 
The colour ratio in F, suggests that at least two pairs of Mendelian 
characters are concerned which appear to be (1) presence (C) and absence 
(c) of colour, presence being dominant and absence recessive ; (2) grey (G) 
and black (B) colour, grey being dominant and black recessive. 
In that case the gametic formula of the ‘Belgian Hare’ would be 
(C+ G), and that of the ‘White Angora’ (c+ B); the new character 
‘black’ which appeared in F, being thus introduced by the Albino Angora. 
From this it would appear that the coloured coat of a rabbit is due to 
the meeting of two distinct gametic factors, one of which may determine 
the presence of the pigment, while the other determines the colour of 
that pigment. If, for instance, C be present, the animal will be coloured, 
if absent it will be white ; if both C and G be present it will be coloured 
grey, while if C and B be present it will be coloured black. 
These results with rabbits confirm Prof. Cuénot’s experiments and 
conclusions with similar coat-colours in mice. 
Since my results were published, Mr. Bateson has suggested that in 
such cases the coat-colours may be due to at least three pairs of gametic 
factors, viz. (1) presence (C) and absence (c) of colour; (2) presence 
(G) and absence (g) of grey ; (8) presence (B) and absence (b) of black ; 
presence being dominant and absence recessive in each case. In that case 
the gametic formula of the ‘ Belgian Hare’ would be (C+G+B), and that 
of the ‘ White Angora’ would be (c+g+B), both being homozygous in B. 
Hither interpretation covers the known facts, and further experiments 
are necessary to determine which is correct. In any case, however, it is 
clear that the pure-breeding grey coat-colour of the ‘ Belgian Hare’ is a 
compound character represented in the gametes by at least two distinct 
factors. 
THe Rose ComB oF THE ‘BuAcKk HAMBURGH’ Fowt. 
In my experiments the pure-bred ‘ Black Hamburgh’ with a rose 
comb, crossed with the pure-bred Houdan with a leaf comb, gave in F, 
cross-breds with modified rose combs. In F, there appeared a small 
proportion of true single combs (7 in 70). These results suggest that the’ 
homozygous rose and leaf combs are not simple Mendelian characters, 
but are probably compounds cf rose on single, and leaf on single, respec- 
tively. In rose crossed with leaf combs, the two pairs of Mendelian 
of the flower, the yellow palate and the yellow hairs within the corolla tube are 
common to all the three races and evidently belong to an independent Mendelian 
character, all three forms being homozygous in that character. 
With regard to the remainder of the corolla tube, this is white in ‘ White Queen’ 
and ‘ Yellow Prince,’ and amaranth-red in ‘Crimson King.’ When ‘Crimson King’ 
was crossed with ‘ White Queen’ and with ‘ Yellow Prince’ all the cross-breds had 
red corolla tubes in F,, while in F, segregation into red tubes and white tubes took 
place among the reds only, all the whites and yellows having white tubes. Further 
experiments are necessary to determine the precise nature of these ‘ Delila’ forms. 
