THE DIGESTIVE SYSTEM 63 



12). Since the teeth of the two sides are alike, the dental formula 

 has been used as a short method of indicating the number and 



Fig. 12. — Skull of adult seulpturorl to show embedded parts of teeth: 

 Ii, I2, I:i, Incisors; C, canines; 1, 2, 3, 4, .5, (>, mohir teeth numbered without 

 reference to the first premolar, which is not pre.sent in this .specimen. (Si.sson, 

 Anatomy of Domestic Animals.) 



kind of teeth an animal has. It is represented for adult male 

 horses in the following; manner: 



2( lf+cVP]M^^-^+M;M=40 or 42. 



In this formula the letters indicate the kinds of teeth, and the 

 figures above and below the line give the number of teeth of one 

 side in the upper and lower jaw respectively. 



This formula varies from the fact that the loolf teeth may or 

 may not be present. These teeth are classified as upper pre- 

 molars, but in some subjects occur in the lower jaw. There is 

 still a controversy as to whether they belong to the permanent or 

 temporary set. The presence of wolf teeth neither does harm 

 nor causes eye disease or weakness. 



The canine teeth of mares are usually so small that they do 

 not erupt. In 8000 subjects examined by Ellenberger, between 



