SUCCESSION OF THE ELEPHANT'S GRINDERS. 283 



remnant of the third molar is shown at m 3 (Fig. 73). It 

 is probable that the three preceding teeth are analogous 

 to the deciduous molars, c/2, c/3, and c?4, in the hog 

 (Fig. 75). 



The fourth molar presents a marked superiority of size 

 over the third, and a somewhat different form; the ante- 

 rior angle is more obliquely abraded, giving a pentagonal 

 figure to the tooth in the upper jaw (Fig. 73), m 4. The 

 number of plates in the crown of this tooth is fifteen or 

 sixteen, its leno^th between seven and eiprht inches, its 



JO O 7 



breadth three inches. It has an anterior simple and 

 slender root supporting the first three plates, a second of 

 larger size and bifid, supporting the four next plates, and 

 a large contracting base for the remainder. The fore- 

 part of the grinding surface of this tooth begins to pro- 

 trude through the gum at the sixth year; the tooth is 

 worn away, and its last remnant shed, about the twentieth 

 or twenty-fifth year. It may be regarded as the homo- 

 logue of the first true molar of ordinary pachyderms 

 (Fig. 75), m 1. 



The fifth onolar, with a crown of from seventeen to 

 twenty plates, measures between nine and ten inches in 

 length, and about three inches and a half in breadth. 

 The second root is more distinctly separated from the 

 first simple root than from the large mass behind. It 

 begins to appear above the gum about the twentieth 

 year ; its duration has not been ascertained by observa- 

 tion, but it probably is not shed before the sixtieth year. 



The sixth molar is the last, and has from twenty-two 

 to twenty-seven plates; its length, or antero-posterior 

 extent, following the curvature, is from twelve to fifteen 

 inches; the breadth of the grinding surface rarely ex- 



