HEAD AND NECK OF THE HORSE 



89 



called) is conical, curved and well developed, being, in the young animal, 

 two or three times the length of the exposed crown. With age the 

 exposed crown becomes gradually converted into a blunt cone. 



In both the upper and lower jaw there is an interdental space 

 between the incisors and the canines, but the interval is less in the 

 mandible than in the upper jaw. Thus the mandibular canine bites in 

 front of the maxillary tooth, as is the arrangement in mammalia in 

 jjfeneral. 



Cement.^ 



Enamel. 



Dentine. 



■Tooth cavity 



Fig. 32. — Diagram of a longitudinal section of a maxillary cheek-tooth. 



Deciduous canines occur in both the male and the female, but they 

 are always rudimentary and do not erupt. 



The maxillary cheek-teeth ^ are large and possessed of long crowns, 

 the major part of which, in the young tooth, is embedded in the jaw. 

 As wear proceeds the embedded part of the crown emerges, and thus 

 ensures the preservation of a uniform length of tooth above the gum. 

 With the exception of the first, each tooth is in the form of a slightly 

 bent four-sided prism, the first being three-sided in consequence of the 



1 Since the first premolar was described earlier (page 86), it is not included in 

 the above description. What are here named the first, second and third "cheek- 

 teeth" are, therefore, the second, third and fourth premolars. 



