Crossing of Suffolk and Dorset Horned Sheep. 55 
obtain this combination in the stable condition it is therefore 
necessary to test a far larger series of individuals than was the 
case where only one dominant feature had to be considered. 
The combination of two dominants from the animal breeder’s 
point of view means a long series of tests which may prove 
almost prohibitive in practice. 
Crossing of Suffolk and Dorset Horned Sheep. — The 
inheritance of numerous characters in the animal world has 
f>een traced in the same manner as those just described. Thus 
the inheritance of the face colour and horns in sheep has been 
investigated by Wood. 1 The breeds chosen for this purpose 
were Suffolks and Dorsets, the former having black faces and 
no horns, the latter white faces and horns in both sexes. 
Thirty Suffolk ewes, crossed with a Dorset ram, gave forty- 
three lambs, all of which had speckled faces, the black and 
white being distributed in patches. The cross was also made 
in the opposite direction, Dorset ewes being mated with a 
Suffolk ram. In this case also all of the offspring had the 
same type of speckled face (Figs. 4 and 5). The direction of 
the cross, then, makes no difference in the progeny. This may 
be taken as a general rule, and the breeder need not look for 
males carrying the character he requires with the idea that 
they will prove the more prepotent. The faces of the hybrid 
sheep being neither pure black nor white, like those of the 
parents, but a mixture of the two, must be described as inter- 
mediate, neither black nor white being dominant. Thus the 
inheritance of this pair of characters reminds one of the 
inheritance of the lax and dense ears in wheat. 
The next step was to breed from these hybrids. A Suffolk- 
Dorset ram was saved, and crossed with a number of females 
of the same descent. Unfortunately, the animals were young 
to breed from, and only a small number of lambs was secured. 
Five of these had pure white faces, two speckled, and one black. 
The numbers are too small to indicate what proportion of each 
type would occur in a large flock of this descent, but small as 
they are, they show that the result of mating together the 
hybrids is to produce once more the characters seen in the 
parents, together with further hybrid, that is, speckled faced, 
individuals. If we may judge from analogy, and it sqems safe 
to do so in this case, it would be hopeless to attempt to obtain 
a pure race of these speckled faced sheep by mating black 
and white ; each year they would simply throw half as many 
black or white faced individuals as speckled. 
Turning now to the inheritance of horns, in both the sets 
of hybrids the animals were horned if males, and hornless if 
females — a curiously interesting result not without a bearing 
1 Wood, Journal of Agricultural Science, Vol. I., page 364. 
