132 OUTLINES or EQUINE ANATOMY. 



stantly maintained. The superior molars present a square, 

 the inferior an oblong grinding surface. The deep-seated 

 surface presents deep pulp cavities into which the portions 

 of the divided pulp fit. 



In some cases premolar or ^^ wolves teeth^' may be found 

 fixed in the jaw in contact with the anterior surface of the 

 first molar. They are small portions of tooth substance, 

 generally forced out by growth of the permanent molars, 

 which occupy more room than the temporary. The 

 canines, tushes, or cuspidati are four in number in the 

 male, and occupy the space between the molars and 

 incisors, being about equidistant from both. The inferior 

 canines are more anteriorly situated than the superior. 

 These teeth present no inf undibula, but have a single fang, 

 and their crown terminates in a point at its fi'ee extremity, 

 at which two ridges which separate it into two surfaces 

 terminate. The external surface is convex in every direc- 

 tion ; the internal surface presents a groove surrounding a 

 prominence. This is the condition of the unworn tooth ; in 

 the mouth of the old animal the crown becomes conical and 

 blunted. In the mare these teeth may be sometimes seen just 

 emerging from the gum, or simply as a papilla changed into 

 tooth substance on the surface of the mucous membrane. 



The floor of the mouth therefore anteriorly and on either 

 side presents teeth, and the mucous membrane from the 

 lower margin of the cheeks and lower lips is reflected 

 upwards to form the gum, and from the teeth on the inner 

 side after passing for a short distance downwards it is re- 

 flected upwards to cover the tongue, which occupies the 

 central part of the floor of the mouth. In doing so it 

 forms a marked fold at the central line anteriorly, which 

 serves to prevent too free play of the tip of the tongue, run- 

 ning upwards from against the symphysis of the lower jaw 

 and enclosing a portion of the two genio-hyoglossi muscles. 

 This is the anterior pillar or fraenum linguae ; on either 

 side of it may be distinguished an opening of a submaxil- 

 lary salivary '(Wharton's) duct, guarded by a papilla 

 termed the " barb." 



The tongue is the organ of the special sense of taste, and 

 is prismatic and thick posteriorly, and terminates in a 

 rounded spathulate extremity anteriorly. Its bulk consists 

 mainly of muscular structure mixed with the fibres of 

 which is much fat. Against the superior surface the fatty 



