xii LIST OF ILLUSTRATIONS 



FIG. 



17. A temporary or milk tooth. (Roberts, The Horse, Mac- 



millan) . ..... ..... 43 



18. Lower jaw of foal from one to two weeks old. (Roberts, 



The Horse, Macinillan) ... . . . , . 44 



19. Lower jaw of the two-year-old colt. (Roberts, The Horse, 



Macmillan) ......... 44 



20. Lower jaw of the three-year-old colt. (Roberts, The Horse, 



Macmillan) . '....,. . . . . 45 



21. Lower jaw of the four-year-old. (Roberts, The Horse, Mac- 



millan) ........ 46 



22. Side view of the mouth of a four-year-old. (Roberts, The 



Horse, Macmillan) . . . . . . . 46 



23. Lower jaw of a five-year-old. (Roberts, The Horse, Mac- 



millan) ..... "... . .' _^._ . 47 



24. Side view of the mouth of a five-year-old. (Roberts, The 



Horse, Macmillan) . . . <.'"': ... 47 

 26. Lower jaw of a six-year-old. (Roberts, The Horse, Mac- 



millan) ....... ... 48 



26. Side view of the mouth of a six-year-old. (Roberts, The 



Horse, Macmillan) . . " . . . . .48 



27. Lower jaw of the seven-year-old. (Roberts, The Horse, 



Macmillan) . . . . . . . . . 49 



28. Side view of the mouth of a seven-year-old. (Roberts, The 



Horse, Macmillan). . . k ... * . 49 



29. Lower jaw of an eight-year-old. (Roberts, The Horse, Mac- 



millan) . . . . . .-..'. . . 50 



30. Side view of the mouth of an eight-year-old. (Roberts, The 



Horse, Macmillan) . . . . . .' . . 50 



31. Side view of the mouth of an aged horse. (Roberts, The 



Horse, Macmillan) . . . . . . . 51 



32. Lower jaw of an aged horse., (Roberts, The Horse, Mac- 



millan) . . . '. . . . . .51 



33. Shows the wear of an incisor tooth at the ages of three, 



four, five, six, nine and twenty years. (Roberts, The 

 Horse, Macmillan) . . ...... 52 



34. Cross section of an incisor tooth, showing how the shape 



changes with advancing years. (Roberts, The Horse, 

 Macmillan) . . . . . . . . .53 



36. Outline drawing of a horse ....... 85 



