THE TEETH OF PROBOSCIDEA. 349 



All observers, however, are not agreed as to its position ; 

 it certainly presents affinities with Perissodactyla, and also 

 with the Rodents, also, perhaps, with the Insectivora. The 



dental formula is i ~ c prm m . 



Seen from the side, the dentition bears some resemblance 

 to that of a Rodent, because the large size of its central 

 incisors, which grow from persistent pnlps, are chisel-edged, 

 and are furnished with a very thick coat of enamel on their 

 anterior faces : the second pair of incisors, which are small, 

 are soon lost. But Hyrax has the full typical number, pre- 

 molars and molars, and the patterns of the teeth are closely 

 similar to those of the Rhinoceros. 



In the lower jaw the middle incisors are small, and the 

 outer ones largely developed, and all persist : their crowns 

 are in a manner trilobed, and they pass in ordinary closure 

 of the mouth behind the upper incisors, where they are met 

 by a dense pad of gum. 



THE TEETH OF PROBOSCIDEA. 



At the present day the Elephant stands alone, removed 

 by many striking peculiarities from the Ungulata, to which 

 it is more nearly allied than to other orders ; but in former 

 days the order Proboscidea was represented by a good many 

 genera, was widely distributed over the globe, and tran- 

 sitional forms linking the elephant with somewhat less 

 aberrant mammalia were not wanting. In this group the 

 incisors grow from persistent pulps, and form conspicuous 



tusks ; the Elephant has i , the Mastodon has i , the 



Dinotherium i 



Two striking features characterise the dentition of the 



