It is evident that the variability of our domesticated bovines, as far as their bodies are concerned, is very great. Between the ancient aurochs and the more highly cultivated of its descendants, the difference is as great as that which separates any other of our captive animals from their wild ancestors. In size, shape, in flesh-and milk-giving qualities, the departure from the old form of the wilderness is remarkable. Moreover, at the present time these diverse breeds of horned cattle are rapidly being multiplied, the distinctive forms probably being twice as numerous as they were at the beginning of the present century. The process of selection has led to some very wide diversifications of the body. The horns, which in the wild state are invariably well developed, and which in the cattle of our Western plains attain very great size, have in certain breeds altogether disappeared, and in their place there sometimes comes a remarkable crest of bony matter which does not project beyond the skin which covers the head. If such differences occurred in the wild state, they would be regarded as separating the two types of animals widely from each other. [Illustration: Egyptian Sheep] In treating the wool-bearing animals along with beasts of burden, we make a somewhat fanciful classification which yet is not quite without reason. By long training man has brought these species to the state where their covering of wool or hair, once a coating only sufficient to afford protection from the weather, has become a very serious load. In certain of our highly developed varieties the annual coat is so far increased that the creature loses a large part of its bulk after the shearer has done his work. Each year's fleece often amounts in weight to eight to twelve pounds, and in its lifetime the animal may yield a mass of wool far exceeding its weight of flesh and bones in any time of its life. When the fleece is mature the animal is often burdened with a load about as heavy in proportion to his size as is a horse by the weight of its rider and accoutrements.