Recent Advances in the Study of Heredity. 247 
DR, viz : h and n, and in one DD, viz : /; and of the 3 GRs the R in 
two cases, viz: l and 0 , is DR and in one, k, it is DD. The zygote 
<? YR 
YW 
GR 
GW 
a 
b 
c 
d 
? 
YR 
YY-RR 
YR 
YY-RW 
YR 
YG-RR 
YR 
YG-RW 
YR 
e 
f 
g 
h 
YW 
YY-RW 
YR 
YY-WW 
YW 
YG-RW 
YR 
YG-WW 
YW 
i 
i 
k 
l 
GR 
YG-RR 
YR 
YG-RW 
YR 
GG-RR 
GR 
GG-RW 
GR 
in 
n 
0 
P 
GW 
YG-RW 
YR 
YG-WW 
YW 
GG-RW 
GR 
GG-WW 
GW 
which bears two recessive characters, the GW (square p) is of course 
homozygous in both respects. It may be noted that the zygotes 
which are homozygous in respect both of colour and of shape, 
lie along a diagonal which traverses the Table from the top left to 
the bottom right corner ; whilst the zygotes which are heterozygous 
in both respects lie along the other diagonal of the Table. 
I think it is desirable to note in passing, that although these 
various zygotic types follow from the theory with which we started in 
constructing the Table, they can also be deduced from a knowledge 
that in the case of cotyledon colour and shape there occur in F 2 
three types of individuals, in each case a pure one bearing the 
dominant character—Y, a hybrid one with the same character— 
(H) Y, and a pure recessive type—G. 
If the two following series of characters, a and b, in the 
a. 1 Y 2 (H) Y 1 G 
b. 1 R 2 (H) R 1 W 
numerical proportions indicated, be distributed at random over a 
number of individuals in such a way that each individual may bear 
any two characters so long as they are not two of the same or the 
two members of a single allelomorphic pair, the numerical pro- 
