342 E..J.: ALLEN AND EB. W. SEXTON. 
The figures given below show the number of offspring obtained in 
our experiments by mating together animals of the constitutions specified 
in each heading. These are summary figures, giving the totals for all 
crosses of each particular kind, and include many cases which are not 
referred to in the previous sections of the paper. The figures demanded 
by theory are placed below those given by our experiments. The total 
number of animals of which both eyes were examined for eye-colour to 
Sept. 8th, 1917, is 26,553. 
The figures are arranged in the following order under the different 
eye-colours :— 
1. The matings giving offspring all of one colour ; 
2. Those giving offspring of two colours in the proportion 3: 1 ; 
3. Those giving offspring of two colours, half of one and half of the 
other ; 
4.-7, Those giving offspring of three colours. 
1. Matings giving normal-eyed* offspring all of one colour. 
Black, offspring all normal-eyed Black in appearance, in agreement 
with theory. Number of young, Black-eyed, 
BxB 215 
Bx B+R 146 
BxB+A 87 
BxB+R+A 17 
BxR 618 
BxR+A 126 
BxA+B 18 
BxA+K 19 
B+RxB+<A 46 
B+AxR 251 
B (half no-white) x BN 15 
BNxB+R+A 92 
A+BxR 87 
A+BxRN 158 Total, 2015. 
Red, offspring all normal-eyed Red in appearance, in agreement with 
theory. Number of young, Red-eyed. 
R x a2? 
RxR-+A 679 
RxA+R 259 
RxRN 24 
RNxA+R 137 
R (half no-white) x RN 20 Total, 2644. 
* In this section the word *‘normal-eved”’ is used in the sense that the chalk-white 
extra-retinal pigment is present. 
