THE INHERITANCE OF PRODUCTIVITY IN FARM LIVE STOCK.            297

But in surveying the wool-producing countries, one cannot help being impressed
by the remarkable way in which certain localities are pre-eminent for selection and
improvement, constituting in effect centres for the breed from which emanate
stock for commercial use in other areas. The type most successfully or most
readily developed in one breeding centre is, however, not necessarily very like
that from another. Further, they do not perforce react in precisely the same way
when transported to yet another environment.

A few instances from the many may be quoted. In the British Isles, is a
multiplicity of breeds, almost every one possessing a territory within which it
either predominates or produces stock for crossing, and there are also local varia-
tions in type of practical importance. In Australia, among the Merinos, are the
South Australian, the Riverina, and other New South Wales forms of strong wools;
stocks of strong or medium wool origin exhibit different characters when pastured
in fine wool areas, whlist among the fine wools, distinction can be made, for
example, between the Tasmanian, Victorian, and New South Wales types. Parts
of the Karroo areas in South Africa form fountain heads of improved breeding
stock for use in other regions of the Union, and in New Zealand, among the
Romneys, different localities apparently demand different strains.

In all cases it is, or should be, the general balance of fleece-characters that is
borne in mind. Only a few days ago, discussion with a New Zealand breeder
revealed that he had been attempting to increase his fleece-weights by selecting
for greater staple-length, but he had found that at a certain stage the wool suffered
by the tips of the staples becoming more weathered and wasted. Thus, it was
better to sacrifice the extra length and weight for soundness throughout the staple.

All these considerations add force to the principle that the pre-requisite for
selection is that environment which allows the clearest expression of genotype.
In the field of wool-productivity, to aid in the recognition of genotype and to gain
accurate knowledge of phenotype to which it gives rise in other environments, are
objectives which the zoologist may well pursue.

                                          REFERENCES

1. W. C. Miller, Empire J. Expt. Agric. 1933,1, 173.
2. A. B. Wildman, Proc. Zool. Soc., London, 1932, 257.
3. F. W.Dry, N. Z. J. Agric., 1933, 46, 10, 141, 279 ; 47, 289.
4. J. E. Nichols, J. Text. Inst., 1933, 24, T 333.
5. A. T. King, and J. E. Nichols, Nature, 1933,132, 966.
6. J.-A. Hill, 34th Ann. Rept. Wyoming Agric. Expt. Stat., 1923-4.
7. C. B. Davenport and E. G. Ritzman, New Hamp. Agric. Expt. Stat. Tech. Bull.
No. 31, 1926.
8. J. E. Nichols, J. Agric. Sci., 1933, 23, 473.