IRREGULARITIES OF THE DENTAL APPARATUS. 



746 



a. Inferior Jaw. — 

 It is rare that the ab- 

 normal wear aifects all 

 the molars on the same 

 side. Sometimes those 

 of the middle are the 

 shortest (Fig. 322), and 

 then the arcade de- 

 scribes, as a whole, a 

 somewhat regular curve, 

 concave from before to 

 behind, in which are 

 placed the superior teeth. 

 Sometimes, on the con- 

 trary, those of the ex- 

 tremities, the anterior 

 or the posterior indiffer- 

 ently, are deformed, and 

 then the middle part of 

 the arcade becomes inore 

 or less convex, according 

 to the degree of the anom- 

 aly (Fig. 323). Here, 

 also, the length of the 

 crown in the two jaws 

 is always inversely pro- 

 portional. 



Another peculiarity 

 is remarked, which con- 

 sists in the separation of 

 the roots in the advanced 

 degrees of wear. They 

 form then so many dis- 

 tinct teeth, and it almost 

 seems that the number 

 of molars is greater than 

 in ordinary conditions. 

 In the specimen pre- 

 sented in Fig. 322, eight 



teeth can, apparently, ^^^ 322.— inferior molar arcade of a very olrl horse, show- 

 be counted ; in that of ing the radical cementation, as well as the insufficient length 



of the middle teeth. 



A, A, vestiges of the roots ; B, B, cement, 

 disappeared. 



The enamel has 



