58 GUIDE TO THE FOSSIL MAMMALS AND BIRDS. 



Pig. 47.— Vertical longitudinal section of molar tooth of Mastodon, showing 

 open valleys between cross-ridges, thick enamel (6), and the dentine 

 (c) ; two-thirds nat. size. (Table-case 24.) 



Fig. 48. — Vertical longitudinal section of molar tooth of Elephas (Stegodon) 

 insignia, from the Lower Pliocene of the Siwalik Hills, India, showing 

 wide valleys between cross-ridges filled with cement (a), the layer of 

 enamel (b), and the dentine (c) ; one-third nat. size. (Table-case 24.) 



—b 



Pig. 49. — Vertical longitudinal section of molar tooth of Elephas plani- 

 frons, from the Lower Pliocene of the Siwalik Hills, India, showing 

 deep valleys between cross-ridges filled with cement (a), the layer of 

 enamel (6), and the dentine (c) ; one-third nat. size. (Table-case 24.) 



