THE TEETH. 355 



convex. The enamel on the approximal surfaces termi- 

 nates in an obtuse angle, with vertex toward the cusps 

 and most readily distinguished on the distal surface. 

 The root is prominent and long, and, on cross-section, 

 like a rounded triangle. 



We are enabled to tell on which side the tooth 

 belongs by the slope from cusp to mesial surface being 

 shorter than that from cusp to distal surface. 



The lower cuspids resemble the upper, but are dis- 

 tinguished by being smaller. The lingual and labial 

 surfaces are more distinctly convex, and the root is flat- 

 tened. The enamel at the approximal surfaces is curved 

 at the neck ; occasionally that of the mesial side is angu- 

 lar, like the upper. 



The bicuspids or premolars have crowns, on section, 

 almost like a rounded square. 



The first upper bicuspid has a buccal and lingual 

 cusp, separated by a fissure, which bifurcates at each 

 termination and runs over on the mesial surface. The 

 former is the larger cusp, and the slope from cusp to the 

 distal surface is longer than that to the mesial. The root 

 bifurcates. The second bicuspid is distinguished by 

 being larger than the first ; the fissure does not run over 

 on the mesial surface, and its root is not bifurcated, but 

 oval, and compressed by a groove which runs down the 

 centre on each side. 



The inferior first bicuspid is the smallest of the bicus- 

 pids, and is the only one which is not marked by a fissure ; 

 the buccal cusp turns in very much, and the lingual is 

 small and often rudimentary. Its cusps are connected 

 by a ridge, on either side of which is a pit. 



The inferior second bicuspid has a semilunar fissure 

 running mesio-distally with its convexity toward the 

 lingual surface, and a second fissure sometimes running 



