234 STRUCTURE AND ADAPTATION OF TEETH 



The crowns of these molars, or rather lacerating 

 teeth, are, like the rest, thickly covered with 

 enamel, and when brought into operation, they 

 act like the antagonizing blades of a pair of metal 

 shears upon the substance submitted to their 

 cutting edges. 



The flesh of their victims is swallowed without 

 much division, and is not truly masticated ; the 

 food, already animalized, not requiring such pre- 

 paration. . 



If we carefully examine a tiger's cranium, we 

 readily see the machinery by which this terrific 

 apparatus is set in motion. The occipital crest is 

 a sharp and prominent long ridge, rising from the 

 occipital portion of the skull, and continued along 

 the junction of the parietal bones, its chief use 

 being for the attachment of the immense temporal 

 muscles, which would almost entirely cover the 

 cranium, but for their separation by the bony 

 ridge. 



Fig. 34. — Skull of Tiger ^ showhtfi occipilnl crest rit/d zi/gomatic arch. 



