THE MOUTH. 



41& 



one for the secretion of the dentine, lodged in the internal cavity of the tooth, 



and hollowed into a cup-shape at its free extremity ; the other contained in the 

 external cul-de-sac (Fig, 228, a, b, c). 



Tusks, Fangs, or Canine Teeth. ^ — " The tusks of Solipeds only exist in 

 the male ; it being quite exceptional to meet with them in the female, and even 

 then they are rarely so strong as in the male. 



" These teeth are four in number, and are placed one at each side of the 

 jaws, a little behind the incisors, to which the lower canines are much nearer 



Fie. 2"2. 



INCISOR TEETH OF THE HORSE (DETAILS OF STRUCTURE). 



1, A tooth in which is indicated the general shape of a permanent incisor, and the particular forms 

 successively assumed by the dental table in consequence of friction, and the continued pushing 

 outwards of these teeth. 2, A virgin tooth, anterior and posterior faces. 3, Longitudinal section 

 of a virgin tooth, intended to show the internal conformation and structure. Not to complicate 

 the figure, the external cement, and that accumulated in the infundibulum, has not been shown. 

 4, Transverse section for the same purpose : a, Encircling enamel ; 6, central enamel ; c, dental 

 star ; d, dentine. 5, Deciduous tooth. 



than the upper. Between them and the first molar there is left a considerable 

 space, which constitutes the bar of the inferior jaw. 



" The free portion of the tusk, slightly curved and thrown outwards, par- 

 ticularly in the lower jaw, offers two faces — an external and an internal — separated 

 from one another by two sharp borders inclined to the inner side, and meeting 

 in a point at the extremity of the tooth. The external face, slightly rounded, 

 presents a series of fine striae, longitudinal and parallel. 



' The quotations included within inverted commas are from M. Lecoq's Traite de VExt€rieur 

 du Cheval et des Principaux Animaux Domestiques. 



