Mountain breeds always differ from lowland breeds; and a mountainous country would probably affect the hind limbs from exercising them more, and possibly even the form of the pelvis; and then by the law of homologous variation, the front limbs and the head would probably be affected.

The shape, also, of the pelvis might affect by pressure the shape of certain parts of the young in the womb.

The laborious breathing necessary in high regions tends, as we have good reason to believe, to increase the size of the chest; and again correlation would come into play.

The effects of lessened exercise, together with abundant food, on the whole organisation is probably still more important, and this, as H.