but they are occasionally found in the mare, though a small size. (2/4.
'The Horse' etc. by John Lawrence 1829 page 14.) The number of ribs on each
side is properly eighteen, but Youatt (2/5. 'The Veterinary' London volume
5 page 543.) asserts that not unfrequently there are nineteen, the
additional one being always the posterior rib. It is a remarkable fact that
the ancient Indian horse is said in the Rig-Veda to have only seventeen
ribs; and M. Pietrement (2/6. 'Memoire sur les chevaux a trente-quatre
cotes' 1871.), who has called attention to this subject, gives various
reasons for placing full trust in this statement, more especially as during
former times the Hindoos carefully counted the bones of animals. I have
seen several notices of variations in the bones of the leg; thus Mr. Price
(2/7. 'Proc. Veterinary Assoc.' in 'The Veterinary' volume 13 page 42.)
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 (2/8. 'Bulletin de la Soc. Geolog.' tome 22 1866 page 22.), 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. (2/9. Mr. Percival of the Enniskillen
Dragoons in 'The Veterinary' volume 1 page 224: see Azara, 'Des Quadrupedes
du Paraguay' tome 2 page 313. The French translator of Azara refers to
other cases mentioned by Huzard as having occurred in Spain.) 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.