212 



ANIMAL LIFE PAST AND PRESENT. 



the clumsy Khinoceroses and Tapirs, and can only be 

 equalled by that of the Antelopes and Deer. 



The cheek-teeth of the Khinoceroses and Tapirs are 

 formed on a somewhat different plan from that obtain- 

 ing in the previous group, as may be seen by comparing 



FIG. 71. A left upper cheek-tooth of a Rhinoceros-. 



the figure of a Rhinoceros tooth, given in Fig. 71, with 

 the earlier figures. This plan of structure consists, 

 indeed, of an outer wall, with two oblique ridges or 

 crests running towards the inner side of the crown, 

 where they terminate in somewhat expanded pillars. 

 When somewhat worn, the surfaces of dentine on such 



