338 E. J. ALLEN. AND E. W. SEXTON. 
In Brood 23 all the Red-eyed animals had the red pigment much reduced, 
giving a yellow appearance to the eyes, and two had the left eye practically 
no-white. This brood is breeding and has given so far, normal Reds, Red 
no-whites, one-sided Red no-whites and Albinos. 
In Brood 24, the red pigment was greatly reduced, only 2 out of 19 Red- 
eyed showing a faint pink tinge, the others were of a pale yellow tint. Seven 
of them had hardly any white pigment, and in one of them the right eye was 
practically no-white. One Albino had the right eye very small. 
In Brood 25, the coloured pigment in the Red-eyed animals was the normal 
bright red tint, one had very thin reticulation on the left side, one had the 
right eye no-white, and very thin reticulation in the left, one had the right 
eye no-white, with no red pigment in the centre of the eye, two had both 
eyes no-white. 
The last Brood, 26, consisted of only three animals, Red-eyed, with the 
red pigment much reduced. 
(2) The same Red-eyed male (I.F.) was mated with another Red-eyed 
female (1.G.) from the same brood as the last and had in 3 broods 46 
red-eyed and 18 albino-eyed young (Plate I). The 3rd brood consisted 
of 25 red and 12 albino-eyed young. These were left together in one 
bowl, and 15 young were obtained from their chance matings, 4 red, 8 
albino and 3 with colourless eyes on both sides. 
Two of these colourless ones survived, a male and a female (Plate V, 
Fig. 5). For details of offspring, see p. 339.3. 
CONSTITUTION OF THE COLOURLESS EYE. 
That these colourless eyes, whether obtained by breeding together 
no-whites and albinos (see p. 330) or having an independent origin, 
behave as recessives to white and to colour is shown by the following 
results :— 
1. (a) A female with both eyes Colourless (C.27, see p. 333), belonging 
to the F, generation from the mating Albino carrying black crossed with 
Red No-white, was mated with an Albino male (Plate II, VI.B.2.t.) and 
produced 108 young in 5 broods all with the usual albino eyes. 
Two of these broods have reached maturity and from their matings 
218 young have been obtained, 163 with the usual albino eyes, and 50 
albino no-whites. Theory demands for this number 164 albinos and 
54 albino no-whites (Colourless). 
Some of the albino-eyed young of this second generation have just 
become mature, and when mated together gave 19 albino-eyed and 5 
albino-no-whites (Colourless). 
(b) From another mating of this kind, Colourless female with Albino 
male, one brood of 18 young resulted, all with normal albino eyes. These 
