GG GUIDE TO TIIK FOSSIL :MAMMALS AND BIRDS. 



Wall-ease A series of models (jf the skulls of Mocritherium, Faheo- 



mastodon, and Tctrabelodon is arranged for comparative study 

 on the front part of Stand B. 



Tlie fossils, so far as known, sliow therefore that the 

 earliest forerunners of the elephants were small marsh- 

 dwellers which lived on a succulent food in the African 

 region. They gradually increased in size, without essentially 

 altering their limhs and hody ; but as their legs lengthened 

 and their neck shortened, their face and chin gradually 

 became elongated to reach the ground for Ijrowsing. When 

 this strange adaptation liad reached its maximum degree, the 

 chin suddenly shrivelled, leaving the flexiljle, toothless face 

 without any support. Thus arose the unique proboscis of the 

 elephants, which has become prehensile by stages which 

 cannot be traced, Ijecause soft parts are not preserved in 

 ordinary geological formations. 



Starts E,P, j'or comparison, a stuffed modern Indian elephant, a 



' ' ' ■ skeleton of the same, and a newly-born individual of the 



same, are placed in the middle of the Gallery ; while skulls 



and tusks are arranged in the l:)ay between Pier-cases 36 and 



37, and in Wall case 28. 



Order YL— RODENTIA. 



Table-case Fossil remains of rodents or gnawing mammals are common 



^^' in Tertiary formations throughout the M'orld, and a typical 



collection is exhibited in Taljle-case 16. The extinct kinds, 



however, do not differ much from those now living, although 



they can l)e traced back as far as the Middle Eocene period. 



Among the fossil remains of Sciuromorpha, those of the 

 beaver (Castor) are conspicuous. This animal first appears 

 in the Upper Pliocene of Italy, France, and England ; and 

 the common C. fihcr had a remarkably wide range in Europe 

 during the Pleistocene period. Good specimens are shown 

 from the Fen-land (Fig. 63) and from the valley of the Lea, 

 E-ssex. It does not appear to have been exterminated in 

 Britain until about the twelfth century, and there are still 

 allusions to it in some names of places (e.g., Beverley and 

 IS^ant-yr-afancwn). Trogonthcrium cuvieri is a giant beaver, 

 wliich ranged from Pussia to England during early Pleistocene 

 times. A skull, jaws, and other remains from the Xorfolk 

 Forest Bed are exhibited, with plaster casts of a Pussian 

 skull and mandible of the same species. 



