Q Results of Crossing Grey {Home) Mice vnth Albinos 
The actual colours obtained in the 55 F and G families are as follows : — 
23 black, 74 grey, 2 golden agouti, 1 chinchilla, 1 yellow, 6 sooty yellow, 
2 chocolate, 1 yellow marked with white, 24 grey marked with white and 3 black 
marked with white. 
Cross L was made by breeding together those coloured mice which had been 
used in the and (?s and which had produced only coloured young. Their 
offspring were all coloured, consisting of 57 grey, 3 grey marked with white, 
3 black and 5 sooty yellow. 
In cross M the remaining coloured mice which had been used for the and 
(tS were mated together and produced 30 albinos and 71 coloured mice, the colours 
being as follows : — 52 grey, 5 grey marked with white, 7 black, 1 golden agouti, 
6 sooty yellow. 
The white offspring of the ^s were also mated together, and in all cases bred 
true. 
In conclusion, it is hardly necessary to point out that with regard to characters, 
colour-productiveness and albinism the mice under consideration here behave in 
complete accordance with Mendel's laws, both with regard to dominance and to 
segregation. If one considers the nature of the colour and the question as to 
whether it is distributed uniformly or is marked with white there is nothing in 
my results incompatible with similar behaviour with regard to these characters 
also. 
Certain minor difficulties do indeed suggest themselves, for instance the 
occurrence of intermediate forms and the tendenc}' of yellow mice when crossed 
either with white or grey hybrids to produce sooty yellow young; this colour 
figuring somewhat conspicuously in some of the latter generations. 
It is only to be regretted that the true nature of the albinos was not known 
and it is to be hoped that in the future the experiments may be repeated without 
this very serious drawback. 
LIST OF LITERATURE REFERRED TO. 
'02. L. Cu^NOT. " La Loi de Mendel et I'Heredite de la Pigmentation chez les Souris." 
Arch. Zool. Exp. et Gen. Notes et Revue, 1902. 
'03. . Ibid. 1903. 
'04. . Ibid. 1904. 
'03. W. Bateson. " Colour Heredity in Fancy ]\Iice and Rats." P.Z.S. 1903, Vol. n. 
'04. Glover M. Allen. " The Heredity of Coat-Colour in Mice." Proc. Amer. Acad. 
Art. and Sci. Vol. xl. 
DESCRIPTION OF FIGURES. 
These are taken from water-colour drawings ad nat. by Miss Adeline Bitchie. 
(1) Intermediate between grey and black. 
(2) Chinchilla. 
(3) Intermediate between chinchilla and grey. 
(4) Grey. 
(5) , (7), (8) Three shades of yellow. 
(6) Chocolate. 
