ANATOMY 5 



the end of the maxillary bones ; those of very old horses meet at 

 an acute angle, and the teeth appear to project forward from the 

 ends of the jaws. 



Original observations. — The student should make original ob- 

 servations, recording freely by notes and drawings. He should 



Fig. 5. — Twenty Years, Lower Jaw. 



study the part played by individual bones or groups of bones in 

 determining the size and shape of the head. 



Study, e.g., the nasal, frontal, superior maxillary, and inferior 

 maxillary bones. Note what relation they bear to shape of nose, 

 width between the eyes, "coarseness" of the head, and width 

 between bones of the lower jaw. 



A 



B 



Fig. 6. — Grinding Surfaces op Molars. 

 Horse six to seven years old. A, right-hand superior molars; B, left- 

 hand inferior molars. 



Spend as much time as possible in practice at estimating 

 horses' ages by their teeth. Note especially temporary and per- 

 manent teeth present, "cups," and shape of wearing surface. 



Common disorders. — Among the more common diseases and 

 abnormal conditions of the bones of the head and the teeth are: 



