ANIMAL DENTISTRY. 



31 



sharp point. The anterior and posterior surfaces are flat and 

 smooth and come in contact with contiguous surfaces at the 

 crown only. The internal surface is quite smooth and some- 

 what convex from before backward. The table presents 

 the external crusta petrosa, the external enamel, the den- 

 tine, the internal enamel, and the internal crusta petrosa. 

 The edges of the enamel are arranged in the form of the 

 letter "B." (See Figs. i6, 17.) In the center of the internal 



Fig. 14. 

 A Superior Molar, Buccal Surface. 



Fig. 15. 



A Superior Molar, Lingual Surface, 



with Measurement. 



crusta petrosa is a small black spot marking the only open- 

 ings of the infundibula, which are two in number on all the 

 superior molar teeth. The apex presents three to four roots, 

 each having a round opening — the apical foramen. The first 

 molar is triangular in shape, has a sharp anterior face and 

 presents but three roots at the apex. The sixth- is also 

 somewhat triangular with its acutest angle posteriorly, and 

 like the first, has but three roots. 



