656 THE EXTERIOR OF THE HORSE. 



subject. This notch may sometimes be absent, and, in some cases, is 

 rasped off with fraudulent intent before selling the horse. [This notch 

 commences to form at six years.] The table of the inferior intermedi- 

 ates is ordinarily levelled, or at the point of becoming so, and begins 

 to assume the oval form. The central enamel, in the pincers, is smaller, 

 and becomes convex behind. Viewed in profile, the jaws form a semi- 

 circle which is less regular than at six years. (Plate XX.) 



Eight Years. — The incisors have a yellowish tint ; all the lower 

 ones are levelled ; their arcade, quite regular, is narrower transversely 

 than at five years. The pincers are becoming round ; the intermediates 

 are oval ; the corners are becoming oval. The dental star is shown 

 upon the tables in the form of a yellowish transverse line ; it is most 

 marked in the pincers, and often indistinct in the remaining incisors. 

 The central enamel, still less extensive in the pincers, is more angular 

 behind and nearer to their posterior border. According to Mayhew,^ 

 the base of the corner is cut squarely by the gums, which gives to the 

 free part of this tooth a square form. Besides, the mucous membrane 

 is harder, less delicate, and the mouth now seems to have acquired its 

 full strength. The inferior border of the maxillary bone is compara- 

 tively thinner ; the cheeks are flat. Viewed in profile, the opposed su- 

 perior and inferior dental arcades no longer foi'm a regular semicircle. 

 Their arc seems to be broken at the level of the place where the tables 

 meet, and it acquires little by little the curve of an ogive. This re- 

 sults, as we know, from the change in the direction of the teeth, which 

 are now opposed obliquely instead of perpendicularly, as at five years. 

 (Plate XXI.) 



Fifth Period. — Disappearance of the Central Enamel 

 and the Successive Forms of the Dental Tables. — This period, 

 in which it is said by laymen that the horse is old, or marks no more, 

 extends from nine years to extreme old age, and is based upon char- 

 acters less and less reliable. The greater the number of years, says 

 Mayhew,'^ with good practical judgment, the more difficult it is to arrive 

 at an exact determination of the age. After the twelfth year there is 

 but little probability of judging it accurately ; after the sixteenth all 

 is confusion, for there are no positive signs that will enable us to give 

 a definite opinion upon this point, and it is better now to be cautious 

 or remain silent. 



Certain indications are, without doubt, capable of giving rise to the 



1 Edw. Mayhew, The Horse's Mouth showing the Age by the Teeth, London, 3d edition, 

 p. 104. 



2 Mayhew, loc. cit., p. 107. 



