16 



North side, 

 Pier-case, 

 No. 30. 



Molar 

 teeth, of 

 Elephants. 



The Proboscidea- — Elephants. 



Indian and African elephant can also be seen in Pier-case 30, 

 placed near the fossil species, for comparison. 



The teeth in the elephants are composed of numerons more or 

 less closely-folded plates of dentine, coated with enamel, and 

 encased in a thick setting of cement (see Fig. 17), the plates vary- 

 ing in number and in pattern in the different species. Thus the 

 African elephant has few enamelled plates in each tooth, and 

 these on the grinding surface are worn down to a lozenge-shaped 



b'ie. 19. — View of the grinding-surfaee of the second right lower true molar of Elephas 

 antiqum (Falc.) ; £ natural size ; from the Pleistocene of Grays, Essex. 



Fig. 20. — View of the grinding-surfaee of upper molar of Elephas mes 

 § natural size : from the Upper Pliocene of Tuscany. 



dioualis (Nesti); 



pattern (Fig. 16) ; the Indian elephant has many plates, closely 

 folded together and finely crimped at their edges (Fig. 15). 

 The teeth of the larger number of fossil elephants resemble 

 those of existing species, but in some of the earlier forms they 

 Mastodon. approach more nearly in character those of the Mastodon; the 

 ridges are, however, more numerous in the elephant, and the 

 valleys which divide them are filled with cement, but in the 

 Mastodon the spaces between the ridges had little or no cement. 

 Figures 17-23, are given to illustrate some of these variations 

 in the mode of growth and development in the molar teeth of 

 extinct forms of Proboscidea. big. L7 shows, in section, a 

 molar tooth of Elephas planifrons in which all the valleys are 



