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A MANUAL OF DENTAL ANATOMY. 



six months. As the rate of wear is equal, the mark gets 

 worn out soonest upon the central incisors (about the sixth 

 year) in the middle incisors next (about the seventh), while 

 it has totally disappeared by about the eighth year. 



After the " mark " is worn away the centre of the tooth 

 is marked by a difference of colour, due to the presence of 

 secondary dentine, into which the remains of the pulp has 

 been converted. 



FIG. 138 (). 



The molars of the horse are remarkable for their great 

 length ; they do not grow from persistent pulps, but never- 

 theless they do go on growing until a great length of crown 

 of uniform diameter is made, subsequently to which the 

 short and irregular roots are formed. As the upper working 

 surface of the crown becomes worn, the tooth rises bodily in 

 its socket, and when by an accident its antagonist has been 

 lost, it rises far above the level of its neighbours. This 

 elevation of the tooth takes place quite independently of 



( l ) Side view of the dentition of a Stallion. At a short interval behind 

 the incisors are seen the canines ; then, after a considerable interval, the 

 premolar and molar series. 



