60 



GUIDE TO THE FOSSIL MAMMALS AND BIRDS. 



Pier-eases 

 36, 37. 



'Table-case 

 23. 



Pier-cases 

 35, 36. 

 Stand J. 



Table-case 

 24. 



Pier-case 



37. 

 Table-case 



23. 



Pier-case 



38. 



Table-cases 



23,24. 



I Stand B. 



angular roof-like shape of the cross-ridges of the teeth (Figs. 

 48, 51), has these ridges more numerous and usually deeper, 

 while the intervening valleys are partly filled with a soft 

 tooth-substance termed cement. Stegodon is generally re- 

 garded as a sub-genus or section of Mephas proper, and 

 various remains of it from India, Burma, and China are 

 exhibited in Pier-cases 35, 36. A fine skull of Mephas 

 (Stegodon) ganesa with immense tusks (Fig. 59) from the 

 Siwalik Formation, presented by General Sir W. E. Baker, 

 is mounted on a separate stand (J). In the true Mephas 

 the tooth-ridges are excessively deepened and comparatively 

 numerous (Figs. 49, 52), while the intervening valleys, now 

 mere crevices, are filled to overflowing with cement. This 

 progressive complication is well illustrated by a series of 

 sections of teeth arranged in regular order in Table-case 24. 



The Pliocene Stegodon has only been found in southern 

 and central Asia, some of the adjacent islands, and northern 

 Africa. Mastodon, however, ranged over southern and central 

 Europe, and in the Pleistocene period extended nearly 

 throughout North and South America. Among European 

 species may be mentioned M. arvernensis, from the Upper 

 Pliocene of France, Italy, Germany, and the Eed Crag of 

 England, illustrated in Pier-case 37 

 and Table- case 23 ; also M. atticus and 

 M. pentelici from the Lower Pliocene 

 of Greece, exhibited in the same 

 Cases. Among NorthAmericanspecies 

 M. americanus (Figs. 53, 54) is the 

 most important, and is represented 

 not only by the partially recon- 

 structed skeleton (Stand B) at the 

 entrance to the Gallery, but also by 

 numerous remains in Pier-case 38 

 and Table-case 23. It lived until the 

 arrival of prehistoric man in North 

 America, as shown by the occurrence 

 of stone arrow-heads with its bones. 

 The best known South American 

 species is M. humboldti, of which a 

 fine skull is mounted in Pier-case 39 

 (40). Though found nearly all over 

 South America, its remains are especially abundant in the 

 lake deposits or flood deposits in the valley of Tarija, Bolivia, 

 where large herds must have perished. 



Fig. 53. — Lower molar 

 tooth of Mastodon ameri- 

 canus, from the Pleisto- 

 cene of North America ; 

 one - third nat. size. 

 (Table-case 23.) 



