Volume III 
JANUARY, 1904 
No. 1 
BIOMETEIKA. 
ON THE RESULT OF CROSSING JAPANESE 
WALTZING WITH ALBINO MICE. 
By A. D. DARBISHIRE, Balliol College, Oxford. 
The object for which the following experiments were undertaken was to test 
the validity of Mendel's Principles of Heredity, which have recently acquired 
considerable importance, by becoming intimately involved in the question of the 
origin of species. The term Mendelian Principles is used in its widest sense, to 
include not merely the simple Mendelian phenomena of Dominance or Segre- 
gation, but the much more fundamental doctrine of gametic purity. 
Method of Description. 
The method of description employed in this paper is the same as that used in 
the three reports on these experiments which have already appeared : the mice 
are classified, according to the relative extent of the coloured patches on a white 
ground, into six groups. 
Group 1 (Fig. 1) has more white and less extent of coloured patches than the 
normal waltzing mouse. The distribution of colour on a waltzer is shown in 
Fig. 6. 
I wish to draw special attention to the existence of this group, because Castle*, 
who quoted my second paper for another purpose, denies that any mice with less 
colour than a waltzer had occurred in my experiments 
Group 2 (Fig. 2) has about as much white as a normal waltzing mouse. 
Group 3 (Fig. 8) has less white (i.e. greater extent of coloured patches) than a 
waltzer. 
Group 4 (Fig. 4) has still less white, and leads on to 
Group 5 (Fig. 5) which has no pure white, but the belly is whitish, not grey. 
Group G contains mice whose bellies are nearly the same colours as their backs. 
* "Mendel's Law of Heredity," Proc. American Academy, Jan. 1903, pp. 533 — 48. 
Biometrika iii 1 
