70 



THE EXTERIOR OF THE HORSE. 



mana. The external face offers on the median line of the superior lip a small 

 gutter more or less distinct, and on each side an elevation more or less prominent. 

 This gutter is the representative of the nasal gutter, very pronounced in man and 

 some other animals. This lip is, besides, longer, larger, more movable, and more 

 constricted at its base than the inferior. In the latter, on the contrary, the 

 median gutter is absent, to be replaced by some semicircular folds on a hemispheri- 



FiG. 25.— Interior of the mouth (after Bruiieau). 



cal eminence, more or less developed, to which has been given the name of tuft 

 of the chin, and whose base is the mento-labialis muscle. 



The internal face of each lip, concave in every sense, is covered by the 

 buccal mucous membrane, smooth, shining, of a rosy color in good health, and 

 sometimes marbled, due to a deposit of black pigment. This layer becomes 

 reflected on the incisive and inferior maxillary bones, to become continuous with 

 the gums, and lies in contact with the anterior face of the incisor teeth. It 



