DENTAL INDICATIONS OF TIIE AGE OF A HORSE. 219 
four, the central pair of incisors will be nearly perfect, and 
the second pair will have been shed, and a vacant space left 
where they were inserted ; the corner ones will have become 
narrower, and their surface considerably worn down, with 
the mark small and indistinct. The second pair of grinders 
fall at this time. 
At four years the central incisors will have attained their 
full size, and the sharp edge which always accompanies the 
teeth while growing will now be considerably worn off. The 
mark becomes shorter and wider, and more faint, (see fig. 6.) 
The second pair will be grown, but still a little smaller, 
with the mark very deep, and extending entirely across the 
surface. The corner nippers will be somewhat larger than 
the inside ones, although a little smaller than they were, 
and with their surface flat and the mark nearly obliterated ; 
the sixth grinder will have grown level with the others, and 
the tushes considerably developed. The mouth will be still 
shallow, the fore hand of the animal will still be low, and 
with a considerable degree of legginess, which are additional 
indications of the age of the horse. 
The last important change takes place in the mouth of 
the horse between four years and a half to five years. The 
corner incisors are shed, and the permanent ones make their 
appearance ; the central ones are considerably worn, and 
the next pair are beginning to exhibit marks of wear The 
tushes are now fully half an inch above the gums, with an 
external rounded prominence, and a groove on each side. 
Up to the period of the reproduction of the corner incisor 
the animal is designated a colt, but it now assumes the 
name of horse ; the female, which up to this time has been 
denominated Alley, is now called mare. 
The mouth of the horse is nearly perfect at the age 
of five years. The corner incisors are fully developed, with 
