46 
Records of Mice Matings 
skins of these Waltzers were not preserved, but in the case of most of the animals a rough 
appreciation of the extent of the colour patches was conveyed by the use of the letters a and 
/3 and their combination a(i. Figui-e 7 on p. 45 represents an average waltzer = (a/3), all vfaltzers 
with appreciably less colour are noted by a, all waltzers with appreciably more colour by /3. 
With regard to the albino parents we have distinguished ten classes, which are indicated in 
the following manner, the great difficulty is to be certain of the ancestry of albinos bought fi'om 
dealers. In the Index Bt = Bought, Lb = Laboratory-bred. 
Albino Glasses. 
(1) Parents and grandparents all albino, ancestry beyond unknown . 
(2) Both parents albino, but one or more grandparents known not to be albino 
(3) One parent albino, and the other not albino ....... 
(4) Neither parent albino .......... 
(5) Nothing known of ancestry ......... 
(6) Said to be pure-bred albino ......... 
(7) Both parents albino, no definite knowledge of grandparents . 
(8) Back to grandparents all albino, but beyond known to be cross-bred 
(9) Both parents and two grandparents known to be albino, no definite know- 
ledge of the other two 
(10) Back to grandparents all albino, 1 or 2 grandparents pure bred albinos, no 
definite knowledge of others' ancestry ....... 
J 2 
^x3 
^1x2 
Axl 
A\ ? 
^1 
yl2 ? 
^2x 
An 
A\h 
In Weldon's later breeding work on first crossss, i.e. the high numbered QH and \H, he paid 
much attention to the ancestry of his albinos, and the following pedigrees illustrate the ancestry 
in typical cases. The reader must note that the offspi'ing stand at the top of the pedigrees, and 
we descend to parents and ancestry. 
(1) AAZa- Alb. in 1//143, 2>¥152 
? 443*2 (Alb.) = J2? 
from Mottram = /ll 
$ from Austin = /II ? 
(2) AbSa^ Alb. in 2^55 
9/l58a4 (Alb.)=:.l x; 
I 
I 
cross-bred from Steer = Ax 5 from Bacon = .11 ? 
(3) ]//153a» Alb. in 2//124 
$ iHVoSa" (Alb.) /I X 2 
I 
, I 
^ A2ba^ Alb. =42^ 
1 
I 
'Offl03a-' = 3c 
I 
I 
Alb. from Fockelmann, ? Alb. from Steer, ^ Wal3, No. 16 ? $ yll«8 Alb. = .'12| 
No. 89 = /II? No. 88 = .11 I 
Alb. from Bacon, 9 ^1^- from Steer 
No. 57 = /ll ? No. 56 = 41 
