328 E. J. ALLEN AND E. W. SEXTON. 
A Black no-white male mated with a Red no-white female in the same 
brood (C.2.) gave 13 black no-white young. (This Black no-white 
therefore did not contain the factor for red.) 
Brood C.1.b.1., the offspring of a black no-white male (b) with a red 
female (c) both from brood C.1., gave 1 normal black, 3 no-white blacks, 
and 2 no-white reds, which is explained by supposing that the black no- 
white male carries red, and the red female carries the factor for ~ no- 
white.”’ 
Other illustrations are the following :— 
(1) The Red no-white male VII.E. (already used in Experiment (1) 
referred to on p. 327, where it was mated with a hybrid black female) 
was mated with a Red no-white female VII.F. of his own stock 
(Plate V, Fig. 3) and had 26 young in three broods, all red no- 
whites. 
(2) The Red no-white female VII.F. was then mated with the Black 
no-white male (VII.A., see Fig. 1, Pl. V) and had two broods, with 63 
in all, 34 being Black no-whites and 29 Red no-whites. This confirms 
the hybrid (B+R) character of the no-white male, which had already 
been shown in Fig. 1. 
(5) A Black male (BN.) and a Red female (RN.), both no-whites, out 
of the same brood from K stock (VII. G and H), gave in one brood 26 
young, 13 Black no-whites and 13 Red no-whites. 
FURTHER INSTANCES OF ‘“‘ NoO-wHITE” EYES ARISING. 
In the case of the animals already described with which most of the 
experiments on the inheritance of no-white eyes were made, the mutation 
appeared in the hybrid stock. Another instance of a similar origin also 
occurred and was referred to in the former paper, p. 44. In the A family 
7 animals out of 93 surviving produced some no-whites amongst their 
young. Altogether there were 277 of these young, and of these 126 
showed some abnormality in the white extra-retinal pigment. In five 
cases (four black and one red) it was entirely absent in both eyes; in 
five other cases (four black and one red) it was entirely absent from the 
eye of one side only, being normal in the other eye. In the other 116 the 
white pigment was very much reduced in amount and the reticulation 
was much broken up. In extreme cases there were only a few bars of 
white remaining. This gradual disappearance of the white pigment is an 
interesting feature, and might with advantage be studied further by 
means of definite breeding experiments. Other instances of a similar 
kind will be mentioned later. 
No-white eyes have also originated independently of those described 
