10 Feb., 1919.] 



Ageing of Horses. 



103 



At about eight years a transverse white line — the filled fang hole — 

 makes its appearance in front of the mark on the central teeth. In the 

 succeeding year it appear in the lateral incisors, and in the year fol- 

 lowing in the corners. With increasing age it becomes a spot rather 

 than a line, and as the mark disappears it occupies the centre of the 

 table. With increasing age the shape of the table gradually changes 

 from broad oval to triangular, the back of the tooth forming the apex 

 of the triangle, and the teeth become longer and project forwards, 

 meeting each other at an angle instead of perpendicularly as in youth. 



^ 



Plate XI. — At twenty-five years groove has 

 grown down from tlie gum, leaving the upper 

 part of the tooth smooth. 



Plate XII. — ^At thirty years the groove disappears. 



At ten years, Galvayne's mark— a groove on the outside of the 

 upper corner mcisor-^makes its appearance (see Plate VIII.). 



At eleven years it is the size of a grain of wheat, and as the tooth 

 grows _ down more of the groove appears, the length exposed giving 

 some indication of the age. 



At fifteen years Galvayne's mark is haK-way down (see Plate IX.). 

 At twenty years it reaches the bottom (see Plate X.). 

 At twenty-five years it is half -grown out (see Plate XI). 

 At thirty it disappears (see Plate XII.). 



