332 



HISTORICAL PALAEONTOLOGY. 



Siwalik Hills, in India. The fossil forms,, though in all cases 

 specifically, and in some cases even sub-generically, distinct, 

 agree with those now in existence in the general conformation 

 of their skeleton, and in the principal characters of their den- 

 tition. In all, the canine teeth are wanting in both jaws; and 

 there are no incisor teeth in the lower jaw, whilst there are 

 two incisors in the front of the upper jaw, which are de- 

 veloped into two huge " tusks. " There are six molar teeth 

 on each side of both the upper and lower jaw, but only 



i F ih' 247 '~^' M la ^ tooth , of EtePto* Planifrons, one-third of the natural size, show- 

 ing the grinding surface-from the Upper Miocene of India; B. Profile view of the 



one, or at most a part of two, is in actual use at any given 

 time; and as this becomes worn away, it is pushed forward 

 and replaced by its successor behind it. The molars are of 

 very large size, and are each composed of a number of trans- 



