782 



ORGANS OF DIGESTION. 



tooth the angles of which have been removed, so as to leave a single 

 central point or cusp, whence the name cuspidate applied to these teeth. 



this, as 

 thrown 



Fig. 539. Fig. 539. CANINE TOOTH OP THE UPPER JAW. 



a, front view ; &, lateral view, showing the long fang grooved 

 on the side. 



The point always becomes worn down by use. The 

 fang of the canine teeth is single conical, and com- 

 pressed at the sides : it is longer than the faDgs of 

 any of the other teeth, and is so thick as to cause a 

 corresponding prominence of the alveolar arch : on 

 the sides it is marked by a groove, an indication, as 

 it were, of the cleft or division which appears in 

 the teeth next following. 

 a The upper canines, popularly called the eye-teeth, 



are larger than the lower, and in consequence of 

 well as of the greater width of the upper range of incisors, they are 

 a little farther outwards than the lower canine teeth. In the dog- 



Fig. 540. Fig. 541. Fig. 540. FIRST BICUSPID TOOTH OF 



THE UPPER AND LOWER, JAWS. 



a, front view; 5, lateral view, showing 

 the lateral groove of the fang, and the 

 tendency in the upper to division. 



Fig. 541. FIRST MOLAR TOOTH OF THE 

 UPPER AND LOWER, JAWS. 



They are viewed from the outer aspect. 



tribe, and in the carnivora gene- 

 rally, these teeth acquire a great 

 size, and are fitted for seizing and 

 killing prey, and for gnawing and 

 tearing it when used as food. 



The bicuspids (bicuspidati), also 

 called premolars, are four in each 

 jaw ; they are shorter and smaller 

 than the canines, next to which 

 they are placed, two on each side. 



The crown is compressed before and behind, its greater diameter being 

 across the jaw. It is convex, not only on its outer or labial surface, like 

 the preceding teeth, but on its inner surface also, which rises vertically 

 from the gum : its free extremity is broader than that of an incisor or canine 

 tooth, and is surmounted by two pointed tubercles or cusps, of which the 

 external one is larger and higher than the other. The fang is also flattened, 

 and is deeply grooved in all cases, showing a tendency to become double. 

 The apex of the fang is generally bifid, and in the first upper bicuspid the 

 root is often cleft fora considerable distance; but the bicuspid teeth are very 

 variable in this respect, and may be, all four, free from any trace of bifidity 

 of the root. The upper bicuspids are larger than the lower ones, and their 

 cups are more deeply divided. Sometimes the first lower bicuspid has only 



