ncisors 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.

Whether the whole amount of difference between the various breeds be due to
variation is doubtful. From the fertility of the most distinct breeds[111]
when crossed, naturalists have generally looked at all the breeds as having
descended from a single species. Few will agree with Colonel H. Smith, wh