30 



ELEMENTS OF HIPPOLOaY. 



FiGUHE 20. — Longitudinal Sec- 

 tion OP Center Incisoh. 

 Drawn by Capt. C. B. Hagadorn, 

 23d U. S. Infantry. 



Sixth: The direction and 

 length of the teeth. 



As seen in the cut, Figure 20, 

 the tooth in its original shape 

 curves more rapidly towards 

 its outer end. The shape of 

 the remaining portion of the 

 tooth is not altered as the tooth 

 wears off and is pushed for- 

 ward. The height of the mo- 

 lars remains fairly constant, 

 and thus the distance between 

 the jawbones at the outer 

 end also remains constant. 



As the exposed ends of the 

 teeth lose their cuivature and 

 the straighter portion of the 

 original tooth comes into view 

 with advancing years, they 

 meet farther and farther to 

 the front, and the visible por- 

 tion of the tooth becomes 

 longer. Contrast Figures 11 

 and 12. At the same time the 

 teeth become narrower in di- 

 ameter, and so appear more 

 closely bunched in the older 

 animals. Contrast Figures 18 

 and 23. The plumpness of the 

 gums is less in old horses than 

 iUji^young ones. Contrast Fig- 

 ures 11 and 12. 



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