Analysing Hammond's data on the growth of limbs in the sheep, Huxley (1932) found a post-natal simple negative heterogony, or allometry, as in the latest terminology (Teissier, 1937), of the whole limb relative to the body. As lambs, and the young of most other grazing mammals, are born with relatively long limbs enabling them to follow their dams (Hammond, 1932), the same author pointed out that the leg must have exhibited positive allometry during foetal development.

Having possession of a sufficient body of measurements on the skeletal development of female calves of the Chianina breed, a very tall beef and draft breed of cattle of Central Italy, I investigated the course of growth of height at withers relative to the growth of the length of the trunk (from shoulder to ischium). The growth of height at withers can be considered as a sufficiently reliable measure of the growth of forelimb length owing to the fact that the two principal angles in the limb (scapula-humerus and humerus-radius) do not change very much with age (Engeler, 1935).

It was found that the growth of forelimb length in this breed of cattle exhibits a simple negative allometry relative to the growth of trunk length. This simple allometry, with growth constant about 0·78, holds from birth until over the age of 3 years, that is, throughout practically the whole post-natal growth.

Lack of data after this age leaves open to further research the course in the ultimate period of development.

I thought it would be of some interest to compare various breeds of cattle differing rather widely in the absolute values, as well as in the proportions of height at withers and trunk length at birth and in later life.