128 AGE OF THE DOMESTIC ANIMALS. 



IRREGULARITIES IN FORM OF THE DENTAL CUP FISSURE. 



Fissure of the incisor teeth, by faikire of the enamel on the 

 posterior face to completely surround them, is rather more com- 

 mon in asses and mules than in horses. The fissure may 

 represent only a small portion of the tooth, or it may constitute 

 a complete division of the posterior surface, leaving the periph- 

 eral enamel in the form of a crescent (Fig-. 136). 



IRREGULARITIES IN DEPTH OF THE DENTAL CUPS. 



Frequently the dental cup continues on the table of the 

 teeth at a time when it should have disappeared. This occurs 

 more frequently in very well bred horses in which the develop- 

 ment of the teeth has been precocious, and in which tlie teeth 

 have such a consistency and hardness that they do not wear 

 away by use, as they do in more common bred horses. 



EXCESS OF HARDNESS OF THE TEETH. 



The nature of the food which the animal has eaten and 

 the condition of healtli of the teeth are causes which tend to 

 influence this irregularity. It is a condition rarely noticed 

 before the age of seven or eight years. 



The length of the teeth and the form of the dental tables 

 are less to be considered in estimating excessive length of the 

 teeth than is the form of the teeth and that of the cups. 



EXCESS OF LENGTH OF THE DENTAL CUP. 



Sometimes wliile the teeth have worn in tlie ordinary way, 

 have diminished in length, and have undergone the usual 

 changes in the shape of their tables, the cups continue in size 

 and sliape not corresponding with the other indications of age. 



In these, an attentive examination of the tables of the 

 incisors with reference to their shape; the size of the dental star, 

 its situation ; tlie condition of the upper incisors ; the direction 

 of the teeth, tlieir length, color, etc., will rectify the faulty indi- 

 cations furnished by the cups. 



