Of individual variations not known to characterise particular breeds, and not great or injurious enough to be called monstrosities, I have not collected many cases. Mr. G. Brown, of the Cirencester Agricultural College, who has particularly attended to the dentition of our domestic animals, writes to me that he has "several times noticed eight permanent incisors instead of six in the jaw." Male horses alone properly have canines, but they are occasionally found in the mare, though of small size.[103] The number of ribs is properly eighteen, but Youatt[104] asserts that not unfrequently there are nineteen on each side, the additional one being always the posterior rib. I have seen several notices of variations in the bones of the leg; thus Mr. Price[105] speaks of an additional bone in the hock, and of certain abnormal appearances between the tibia and astragalus, as quite common in Irish horses, and not due to disease. Horses have often been observed, according to M. Gaudry,[106] to possess a trapezium and a rudiment of a fifth metacarpal bone, so that "one sees appearing by monstrosity, in the foot of the horse, structures which normally exist in the foot of the Hipparion,"--an allied and extinct animal. In various countries horn-like projections have been observed on the frontal bones of the horse: in one case described by Mr. Percival they arose about two inches above the orbital processes, and were "very like those in a calf from five to six months old," being from half to three-quarters of an inch in length.[107] Azara has described two cases in South America in which the projections were between three and four inches in length: other instances have occurred in Spain. That there has been much inherited variation in the horse cannot be doubted, when we reflect on the number of the breeds existing throughout the world or even within the same country, and when we know that they have largely increased in number {51} since the earliest known records.[108] Even in so fleeting a character as colour, Hofacker[109] found that, out of two hundred and sixteen cases in which horses of the same colour were paired, only eleven pairs produced foals of a quite different colour. As Professor Low[110] has remarked, the English race-horse offers the best possible evidence of inheritance. The pedigree of a race-horse is of more value in judging of its probable success than its appearance: "King Herod" gained in prizes 201,505l. sterling, and begot 497 winners; "Eclipse" begot 334 winners.