DESCRIPTION OF THE PLATES. 



37 



Part of a transverse section of the tusk 

 of an Indian Elephant, showing the de- 

 cussating curved lines of the modified 

 dentine or ' ivory' ; c, the external ce- 

 ment. Original. 



PLATE 147. 



A section of part of the upper jaw, and 

 the last molar tooth of a fossil Elephant 

 (Elephas plani/rons. Falconer) from the 

 Himalayan tertiary deposits ; a a, the 

 common body of dentine ; b, the enamel 

 covering the coronal lamelliform processes 

 of dentine ; c, the thick mass of cement 

 filling the intervals of those enamelled 

 processes, and accumulated upon them 

 in the hinder unworn part of the molar : 

 d d, the roots of the molar. By some 

 unusual accident to the lower opposing 

 tooth of the molar of the opposite side, 

 r, it has not suffered abrasion, but has 

 preserved the mammillated summits of all 

 its plate entire and projecting beyond the 

 level of the grinding surface of the molar 

 in use. Fig. 2. Shows the difference in 

 the surfaces of the right unworn grinder 

 r r, and of the worn left grinder 11; a, 

 dentine ; b, enamel ; c, cement ; ^ nat. 

 size. From the specimen presented by 

 Captain Cautley to the British Museum. 

 Original. 



PLATE 148. 



Fig. 1. Side view of first upper molar of 

 Indian Elephant. Fig. 2. Grinding sur- 



face of same ; both nat. size. Fig. 3. 

 Grinding surface of penultimate lower 

 molar of Indian Elephant. Fig. 4. The 

 same of an African Elephant. Fig. 5. 

 Unusually large last lower molar of the 

 mammoth, {Elephas primigenius) . Fig. 

 6. Penultimate lower molar, of the more 

 normal form and structure of a mammoth. 

 Fig. 7. Part of an upper molar of a 

 mammoth, shewing the transverse ridges 

 on the margins of the coronal plates. Fig. 

 8. Much worn molar of a mammoth. Figs. 

 3 to 8 are ^ nat. size, and in each ; d, is 

 dentine ; d\ the same worn down to com- 

 mon base ; e, enamel ; c, cement ; /, digi- 

 tal summits of coronal plates ; r, root. 

 Original. 



PLATE 149. 



A section of the tusk of an Indian Elephant, 

 magnified 250 linear diameters, showing 

 the microscopic structure of ivory. 

 Original. 



PLATE 150. 



Fig. 1 . A section of a part of the exterior 

 of the root of a molar of the Indian Ele- 

 phant, magnified 600 linear diameters ; 

 d, dentine ; d l , dilated terminations of the 

 undulated tubes ; c l radiated cell of ce- 

 ment ; c n , cemental tubes. Fig. 2. Lon- 

 gitudinal section of the end of a root of 

 the molar of an Indian Elephant, magni- 

 fied 230 linear diameters ; d, dentine ; 

 e c, cement. Original. 



Note by Publisher. — In the foregoing list, Numbers 1, 2, 70, 73, 75, 87, 89, 113, 

 119, 122, are repeated twice, and Numbers 62, 63, 64 and 65, thrice, making a tolal 

 number of 168 plates. 



VOL. II. 



