It has been noticed more than once in the preceding pages that a young animal showing reversion is strong and vigorous. It is the belief of dog breeders that those members of an inbred litter which show reversion are the strongest and best. Similarly, experience shows that if an inbred sire and dam produce a dun-colored striped foal it almost always turns out well. Reversion is accompanied by a rejuvenescence; it is as though the young animal had appeared at an earlier period in the life history of the race, before the race had undergone those changes in the way of deterioration which so often accompany inbreeding. Wild animals are frequently thought to be prepotent over tame ones, but of the eleven zebra-hybrids bred at Penycuik only two took markedly after their sire, the zebra Matopo.[B] There are other experiments recounted which tell the other way, and at present this matter remains in a state of considerable uncertainty. [B] The illustration shows the difference between the facial marks of the zebra and those of the hybrid. The latter, in this respect, bears much the same relation to the former as a blue-rock pigeon does to a fancy type. This article must not close without a word or two more about the zebra-hybrids. It is mentioned above that only two out of the eleven which have already been born took strongly after their father. [Illustration: ROMULUS.] [Illustration: MATOPO.] Those who have seen the young hybrids playing about in the fields at Penycuik must agree that they are the most charming and compactly built little animals possible. Of Romulus, the eldest of the herd, Professor Ewart says: “When a few days old [he] was the most attractive little creature I have ever seen. He seemed to combine all the grace and beauty of an antelope and a well-bred Arab foal.... What has struck me from the first has been his alertness and the expedition with which he escapes from suspicious or unfamiliar objects. When quite young, if caught napping in the paddock, the facility with which he, as it were, rolled on to his feet and darted off was wonderful.” The writer can fully confirm all the praise Professor Ewart lavishes on his pets; in truth, Romulus has been well described as a “bonnie colt with rare quality of bone ... and with the dainty step and the dignity of the zebra.” Remus, the offspring of the Irish mare, has been from the first more friendly than his half-brother; he objected less to the process of weaning, and, if he survives, promises to be the handsomest and fleetest of the existing hybrids.