544 P. W. WHITING 
Dr. C. C. Little showed me a black and white cat with odd 
eyes. The hair surrounding the blue eye was white, while that 
about the yellow eye was black. Blue eyes in pigmented cats are 
rare, except of course in the case of the Siamese. 
I would suggest, therefore, as a working hypothesis that the in- 
cidence of white-spotting in connection with the dominant white 
factor produces the blue eye, or in other words a ‘white spot’ 
about the eye of a white cat makes the eye blue, while a ‘pig- 
mented spot’ about the eye of a solid white cat makes the eye 
yellow. It may be also that a ‘white spot’ in the ear of a white 
cat makes it deaf. This would explain why it is so difficult to 
get blue-eyed white cats with normal hearing as it would be 
difficult to localize the ‘white spot’ upon the eye and to keep it 
away from the ear. This may also explain why odd-eyed cats 
are frequently defective in hearing only on the side having the 
blue eye, as noted by Przibram. It would not be a difficult 
matter to test this hypothesis. 
C. Solid yellow and yellow-spotting 
The tortoiseshell cat has been the subject of much interest 
and discussion in genetic literature dealing with sex-correlated 
phenomena. 
Doncaster (05) considered the problem and tried to explain 
the peculiarities of inheritance by variations in dominance. 
Little (12) suggested the hypothesis of a single sex-linked pair 
of allelomorphs with the male digametic. He used the term 
‘sex-limited character,’ which has since been restricted to simple 
Mendelian heredity in which sex reverses the dominance of the 
allelomorphs. Doneaster (’12) accepted Little’s suggestion as 
in general satisfactory, but pointed out that occasionally black 
females are produced from matings of black female by yellow 
male. According to Little’s hypothesis, the females should 
always be tortoiseshell from the reciprocals of black by yellow 
and the males should be like the mother, disregarding of course 
dilution, tabby, etc. Doncaster suggests an occasional break 
in sex-linkage to explain these anomalous blacks, as also the 
