The horse of more Southern origin thus recognised as distinct from the prehistoric European horse, it is now convenient to speak of as the Southern or Arabian horse. There are certain curious structural features which seem to mark these horses and their offspring, even when their strain is blended with that of the more Northern horse. Probably from the time of the cave-men onward the selective breeding of horses has been carried on, so that in many breeds size has been vastly increased. It is an important fact that the English racehorse has never been selected and bred for “points” (as cattle and sheep are), but always by performance on the racecourse. Thus it becomes an extremely interesting matter to see what are the changes which the breeder of thoroughbred stock has unconsciously produced—what are the differences between the racehorse of to-day and that of 50, 100, and 150 years ago. This was pointed out to me by the late Duke of Devonshire as a reason for supporting my proposal to secure and place in the Natural History Museum the skulls, limb-bones, hoofs, and other indestructible parts of great racehorses (and of other breeds), and also for having very accurately measured reduced models made of such horses, in order that we may after some years compare the proportions and structure at present arrived at with the later developments which the continual selection of winner’s blood in breeding must unconsciously produce. Such a collection was started by me in the museum, but it needs the assistance of owners of horses—both as to placing record specimens in the museum and in paying for the preparation of accurately reduced models by competent artists. It already comprises the skulls of Stockwell, Bend Or, and Ormonde, and several carefully made reduced models of celebrated horses. There is no doubt that the English racehorse has increased in size. He is a bigger animal to-day than he was 200 years ago, and the opinion of the best authorities is that he has increased on the average an inch in height at the withers in every twenty-five years. The racehorse has a much longer thigh-bone and upper-arm bone (in proportion to the rest of the leg) than has the cart-horse, and it is probable that this length has been continually increased by the selection of winners for breeding. There are other points of scientific interest as to modern horses and their forefathers which are illustrated by valuable specimens and preparations placed by me in the Natural History Museum.