NEO-MENDELIAN HEREDITY IN ANIMALS 43I 
The ratios given are the theoretical ratios for a trinybrid Mendel- 
ian experiment, and the actual results have closely approximated these. 
Asa matter of fact, sixteen albinos appeared, and it is not possible, 
except by breeding, to tell one kind from another. Breeding each 
with, for example, Silver-fawn would readily reveal the differences; 
for the F, generation would all be of the color that is masked by the 
lack of C in these albinos. In the Janguage of Johanssen there is only 
one albino phenotype, but there are four albino genotypes. Similarly 
in experiments (z) and (4), which have just been described, the indi- 
viduals are all Black (phenotypically identical), but that they are not 
genotypically alike is clearly shown by inbreeding them. In experi- 
ment (1) we get only individuals of the four color types, while in 
experiment (4) we get, in addition to the four color types, four albino 
types. 
CASTLE’S GUINEA PIGS 
Professor W. E. Castle was one of the first zodlogists to use Men- 
del’s methods. He soon discovered that in the determination of the 
coat characteristics of guinea pigs at least three sets of factors were 
necessary, as follows: 
C=colored fur 
c=albinism (absence of C) 
S=short fur 
s=long fur (recessive to 5S) 
R=rosetted fur 
r=smooth fur (absence of R) 
An example will show how these factors segregate: 
P Colored, Short, Smooth Albino, Long, Rosetted 
(CSr) (csR) 
F, 100 per cent Colored, Short, Rosetted (CSr-csR) 
Colored Colored Colored Albino Colored Albino 
Short Long Short Short Long Short 
Rosetted Rosetted Smooth Rosetted Smooth Smooth 
27 9 9 9 3 3 
F2) albino Albino 
Long Long 
Rosetted Smooth 
3 I 
