22 THE MASTODON, 



tuberosities or processes with rounded points, disposed in 

 Figure 4. pairs to the number of four or 



five, according to the species. 

 An illustration of the grind- 

 ing tooth of the M, giganteus 

 is given in Figure 4. 



The teeth are composed of 

 dentine and enamel, the lat- 

 ter being spread over the 

 crown of the tooth, and the 

 Grinding Tooth of the" transverse ridges not filled 

 up with cement as in the ele- 

 phant. The teeth have no relation whatever to the car- 

 nivora ; for, although having an external covering of en- 

 amel, they are destitute of the longitudinal, serrated cut- 

 ting edge, as exhibited in the flesh-eaters, and by use the 

 protuberances become truncated into a lozenge form. The 

 whole structure of the teeth fitted them for the grinding 

 and mastication of tough and hard vegetable substances. 

 The number of the teeth, in some species, was six on each 

 side of each jaw, making in all twenty-four. They did 

 not all appear at the same time, but were developed in 

 succession, in proportion to the waste of those which pre- 

 ceded. The upper teeth are a little wider than the lower. 

 The first three are wider behind than in front ; the two 

 next, square, and the last terminates in a blunt point. 

 Eight deciduous, or milk teeth, two on each side of each 

 jaw, are developed soon after birth, and shed at an early 

 period. Soon after these teeth make their appearance, 

 a third deciduous tooth is produced, somewhat larger and 

 more complicated, constituting the first three ridged, six- 

 pointed molar ; then follows a fourth of the same form as 

 the third, though greater in size. Sometimes these four 

 teeth in each side of each jaw, sixteen in all, are found 

 co-existing. Following the fourth tooth a fifth is devel- 



