126 



AGE OF THE DOMESTIC ANIMALS. 



Tush Teeth. — Goubaux reports a case of an ass with a 

 supernumerary tush tooth which seems unique (Fig. 131). 



Fig. IMl. 



Molars. — Supernumerary molars have only been Ibund in 

 the upper jaw. They occur sometimes in line in the normal 

 arch, at other times protrude to the outer side, in which case 

 they may cause trouble by wounding the cheek. They have 

 also been found under the zygomatic process at the base of the 

 ear, where they may cause an abscess which opens on the exte- 

 rior, and have been known to protrude into the cranium. 



Figure 132 represents a sub-zygomatic 

 molar, natural size, removed from an abscess 

 under the ear of a three-month-old gelding, 

 by Dr. W. J. Martin, of Kankakee, Kansas. 



DIMINUTION. 



Diminution in the number of the incisors 

 Fig. 1.32. is less froqucut than the presence of super- 



numerary teeth. Diminution should not be 

 confounded with cases of tardy eruption ; nor with those cases 

 of arrest of development, in which the teeth remain in their 

 alveolar cavities ; nor with cases of fracture or surgical injuries 

 and loss of teeth. Diminution includes only the complete abor- 

 tion of the dental follicles, and can sometimes only be deter- 



